Following on from this question, I am interested in finding out how you could measure the popularity of any and all programming languages.
As professional developers, we need to be aware of the trends in the software industry - what languages will employers be looking for in the coming few years, and we should be proficient in. Also, it can allow us to spot opportunities - perhaps there are opportunities for new developers to branch out into mainframe programming as older members of the profession retire. For this reason, it is important for us to track programming language popularity.
There are number of questions already on Stack Overflow (here and here) about how SO could be used to measure a language's popularity (or the difficulty in using said language). Other methods include tracking job adverts (i.e. http://www.hotskills.net/) and search engine query statistics (i.e. http://langpop.com/).
Can the SO community think of any other methods of measuring this?
Summary
Use Stack Overflow tags to measure language popularity
Search Engine query statistics
Job adverts
Open Source code repositories
As noted by various contributors below, each of the above sources has problems as a reference to calculate language popularity/usage.
As the author of http://www.langpop.com my approach is to find as many metrics as possible (certainly not limited to just search engine results! We have books, job listings, irc, google code, freshmeat and others) and let people see the methodology, making the whole thing as transparent as possible. That's why I added the javascript feature that lets you recalculate the normalized results with different weights for each metric.
As someone else notes, there are many different ways of measuring popularity. Another important one that he doesn't mention might be the "acceleration" of a given language: for instance, Cobol has a big installed base, but I don't think a lot of new Cobol projects are being started. Something like Ruby is probably the opposite - it's not widely used, but a lot of people are picking it up for new projects.
I disagree with the conclusion that the numbers are "meaningless", though. By looking at the different measurements and thinking about them some, I think there are plenty of interesting conclusions to be drawn. Also, don't confuse "rough" numbers with "useless" numbers. I think we can definitely say that Java is more popular than Tcl, for instance.
I'd say a language popularity and success is exponential to the number of people who hate it.
Not voting the question down, because a lot of people ask about this kind of thing. However...
The next words out of anyone's mouth after this is asked should be, "Popular with who?".
Popular is a useless word to apply to programming languages. There is no universally accepted meaning of it, so there's objective way to measure it.
For example, the obvious thing to do would be to go out and count up worldwide deployed LOC in every software project in use. When you do that, you'd discover that hands-down the most popular language is Cobol.
Someone else might think the obvious way to measure would be by Google hits. Doing that, they'd find that Java gets 282 million results, while C# gets 48 million, and Cobol only gets 6.5 million. So clearly Java is more popular than C#, and way more popular than Cobol.
A third person might think the obvious way to check is to look at SO tags. They'd find the single most used tag here is C# (34K uses so far). Cobol only has been used 65 times here. So clearly C# is the most popular, and almost nobody uses Cobol.
So who is right? All three are. It depends on what you really meant when you asked the question.
For those who are surprised at my Cobol assertion, I suggest reading this (somewhat dated 2003) article on the subject. It will be a real eye-opener. It could be argued that we non-Cobol programmers are all working around the margins of a gigantic Cobol world.
You check the tiobe statistic
What does "popular" mean? Here are some potential ways of measuring it:
The number of developers writing with that language professionally at a given point in time.
The number of people frequently experimenting with or using the language at home at any given point in time.
The number of developers who wish they were using language X (or are happy that they are).
Problems with some measurements:
Using SO questions or Google hits could merely indicate which language (among those in the running for most popular) is the hardest to use.
Counting job adverts would be horribly inaccurate, since people tend to switch to things that don't fall into their original job description, and you would miss all the people currently using a language (not applying for a job).
Personally, I'd like to use number 3 as a measurement of popularity, but I have no idea how you would measure it. The internet would seem like a good place, but which site will be able to attract all the developers, and how would you know that enough of them responded to the poll?
Open source contributions perhaps.
number of posts about that programming language on stack overflow
You can use Google Trend to have an idea. Of course it's not very accurate since you can write "C#" or "C Sharp" but it can give you a brief idea.
This blog article neatly summarizes the various ways of determining the popularity of a programming language:
Determining Programming Language Popularity
The article describes one way of measuring popularity that has so far not been mentioned:
Popularity by Book Sales
In terms of ways that have been mentioned, the article offers specific ways of gathering statistics:
Measured by Commits to Open Source projects - use of the Ohloh website.
Popularity by Lines of Code - use of figures compiled by BlackDuck
Related
I'm a second year Computer Science student, and am currently applying for jobs for the Summer '11 coop term, this will be my first.
I have found a lot of the jobs 'perfect' candidate have many technical skills I do not possess.
For example, one which I have an interview Monday for, uses Java Enterprise Edition, but I've only used regular Java. Also many things I have no experience with whatsoever, like XML, Adobe FLEX, and Ruby.
Obviously the employer is not expecting a potential employee to have all of these skills, but I was wondering how difficult it would be to pick them up?
I have a strong knowledge of C and Java, and of many concepts and data structures.
With this in mind, is it difficult to pick up languages like Ruby or less related tech like XML or AJAX for example?
Or if I have a good background in compsci, do the concepts apply broadly, and mostly it's just the syntax and rudimentary concepts I will need to pick up to get started?
Please if you have any advice, feel free to share.
Thanks for all your help!
PS: I noticed that most people seem to call Java Enterprise 'J2EE' isnt it now just 'Java EE'? Whats up with that?
Once you've mastered one programming language, you'll easily catch up on a whole family of related languages. The differences are more than just syntax, but there is more or less a fixed set of features that most of the popular languages provide.
A good way to gather programming experience would be to become very proficient in at least one language. I don't know what your experience with C is, but unless it's over 3 years it won't take you much time to get to the same level in any other language, and it won't be too hard anyway. If you ask me, knowing C is a "must" because you learn a little about how the computer executes your programs. Some of the higher-level languages have been (initially) implemented in C themselves.
I'm not a Ruby programmer but i'm guessing it's not a big deal if you already know some C and Java. It's probably even easier to learn than those two. XML is just a data format, and AJAX is a buzzword for "doing stuff dynamically in the browser-based client side of a web application". So there isn't much "tech" to learn here, it's just a matter of knowing and mixing skills to get that kind of thing done. (Basically you'll need to learn at least a little bit about javascript, HTML and HTTP, and know how browsers and web servers work).
Computer science is a branch of mathematics, and as such it will always be relevant. Learning about specific algorithms, data structures, etc. is important but more important (from a practical point of view) is the knowledge of how algorithms or data structures perform, how they can be analyzed, what affects their performance, etc. If you got the basics, you can always open a book by yourself and learn more algorithms and data structures, and it's probably a good idea.
Finally, a useful set of things to know in today's software world is: networking (esp. TCP/IP and HTTP), C, Java / C# or both, minimal knowledge of Javascript, and a little experience with programmatic access to XML
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The amount of available programming languages is both a bless and a curse, I think.
I know a lot of programming languages already, some at syntax-level only and some good enough to do actual coding (Python, C, C++, Haskell, Perl, BASH, PHP, and lots of others). I have been programming for almost as long as I've been intensivly using computers (6 years), in almost every paradigm (functional, imperative, object oriented), but I don't feel prepared for the software industry.
I've been writing a lot of bigger programs in a lot of different languages, mostly network based, including large multithreaded server/clients, and I still don't feel prepared!
Currently I'm obsessed with my "3-tier" plan, which includes a high level language like Haskell, an interpreted language like Python and a low level language like C, yet I don't feel good enough!
I know how to work in teams, and how to work along given guidelines, but I'm unsure.
Am I prepared?
Please, kind people of stackoverflow, help me out of this mess! :(
Thanks for all the answers, I wish I could chose more answers as THE answer :)
Sounds like you know an awful lot about programming, but you don't mention anything else. Being a software developer requires more than just programming as a technical skill. Brush up on topics such as source code control, unit testing/test-driven development, continuous integration, etc. Hopefully you'll land in a job where at least one of those is in use. Try and learn as many useful time-savers as you can with your tools; try to become as flexible and efficient with your IDE as possible.
Elsewhere, don't forget to develop the more personal skills; attitude and work ethic, and more related to your field, issues such as eliciting requirements, documenting issues and describing problems and solutions. Don't worry too much about these if you're going in afresh, because you're not expected to have a huge knowledge of them, but if you're at least aware of them and trying to improve, then you have a greater chance of doing so.
Try to appraise yourself of general software development issues that aren't directly coding, if you haven't already - general attitudes to security-oriented development (and testing), good design and similar best practices.
Don't sweat too much about being perfect right off the bat. If you've got no room for improvement, you aren't going to enjoy your career very long, and burning out as a programmer ain't much fun.
You know enough - there is a minimum threshold of knowledge required in the industry (which is above what some developers have), but it sounds like you are already there.
For anyone with the aptitude, new programming languages, techniques, etc, are easy to learn. A good company to work for will hire you based on your abilities, not knowledge (which can go stale very quickly).
If you want to stand out as a software developer, ensure you have rock solid communication skills for reports, e-mail, telephone, meetings, etc. That is a rarer gift in the software field, and although it is not necessary more valuable at the junior levels, it pays off in the long run.
The single most important thing I can think of to be successful in the industry is to be able to respond quickly and efficiently to change.
I recently took a programming test which I thought was a good and fair test. I passed it without a great deal of effort. I was told that 50% of the people (these are all people with programmer on the resume) don't even know where to start. Your earnestness and desire will most likely put you in the top third of most places to start with.
Knowning languages is not all you can do.
If you can, a placement/internship will do wonders. Anyone can program. Real world experience will teach you more than any tutorials, self learning or schooling will.
Naturally, gaining an internship requires some experience, so it's very much catch twenty two.
If going for an internship is not possible, get involved with an open source project. You'll find you'll learn loads by working with people smarter than you.
True knowledge exists in knowing that you know nothing.
Socrates some smart dude
I think this is pretty common among developers. Imo it´s a way better sign then if you would come to the conclusion that you were fully trained.
The only way to know for sure if you're prepared is to try. Sometimes being thrown in the deep end actually helps and you'll find you learn more in that first real world job than you did in all the books/etc that you read in the years before. Also, knowing multiple languages helps you understand underlying semantics of programming in general, but in a real job you'll likely be sticking to one or two languages day to day, so don't get hung up on knowing every language out there.
It's better to try & fail than to spend your life wondering if you're ready.
Go to dice or monster or whatever your favorite job site is and see what people are looking for. It's not Haskell, it's C++. Learn that well and you're ready to go. Once you're out in the real world, you'll learn quickly enough the things that are important. These are mostly the soft skills that school doesn't teach you. Things like how to get along with the clueless, how to present your ideas so they'll actually be considered, and how to see the forest even though you're stuck under a rock.
I need to find figures that show how many programmers world wide, has each of the following languages as their primary programming language.
C
C++
C#
Object-C
Java
JavaScript
VB.NET
VB6 (or older)
VBA
PHP
flash scripts
Ruby
Does anyone know of such comparison figures?
If not. Do you know of a good way to research this?
I could compare the number of tags here at stackoverflow and the number of articles for each language at sites like codeproject. This would give me a good idea.
But if you can suggest other ideas how to find these numbers I will be greatfull.
/Thomas
A very common site that does this is the TIOBE index. It basically searches for programming languages in major search engines and compares the results, and it shows you some history. The only problem is that C/C++/C# are not distinguished very well, therefore C is more dominant than you'd expect (not to mention that search results include many pages where many languages are listed, like programming FAQs). But in general, TIOBE gives a good idea, I think, and it should get better, since at least Google tends to know the difference between zero, two or four pluses.
Have you tried TIOBE index?
In general this is hard to measure because every approach has a lot of drawbacks.
TIOBE and others that are based on search results e.g. do not tell anything of what is actually used but just what is highly ranked by google (You can even see that just Google changing a bit of their results in 2004/2005 completely mixed TIOBE). And moreover they have the problem that lots of search-terms are ambiguous (Like Java which IS also an island, Ruby which also exists as gem, Python which is a snake and others which have alternative meaning). Another problem with search based is that most things put into the web stay up forever which means it is irrelevant if it is CURRENTLY interesting. If a C resource was put up in 2002 it likely still is available today (which hugely overrates leading or older languages.)
Here one is an interesting approach based on the number of book sales. (This at least eliminates the ambigous problem, but comes with others.)
Wikipedia also has a small article about the topic.
Try Google trends (see an example). In addition, check sites like freshmeat.net and note the number of projects in each language. That's only open source projects and many people will use a different language for their hobby projects than at work (i.e. one that sucks less).
Next, look for sites which offer job openings. I don't have a good link handy but this Google query should get your started.
not yet!!!!!!!
That's only open source projects and many people will use a different language for their hobby projects than at work (i.e. one that sucks less).
Next, look for sites which offer job openings. I don't have a good link handy but this Google query should get your started.
The title may seem slightly self-contradictory, and I accept that you can't really learn a language quickly. However, an experienced programmer that already has knowledge of a few languagues and different styles (functional, OO, imperative etc.) often wants to get started quickly. I've seen a few websites doing effective "translations" in the form of "just show me syntax equivalence". I can't remember the sites now, but for related languages (e.g. Perl/PHP) it's quite common.
Is there a better resource that covers more languages? Is there a resource that covers idioms as well as syntax? I think this would be incredibly useful for doing small amounts of work on existing code bases where you are not familiar with the language. Looking at the existing code, as we know, is not always a good indicator of quality. Likewise, for "learn by doing" weekend project I always have the urge to write reasonably idiomatic, clean code from the start. Such a resource could also link to known good example projects of varying sizes for those that prefer to learn by reading. Reading a well-written medium sized code base can also be much more practical when access to development environments might be limited.
I think it's possible to find tutorials and summaries for individual languages that provide some of this functionality in disparate web locations but I'm hoping there is a good, centralised, comparative place that the busy programmer can turn to.
You generally have two main things to overcome:
Syntax
Reference
Syntax you can pick up fairly quickly with a language tutorial and a stack of samplecode.
Reference (library/API calls) you need to find a proper guide to; perhaps the language reference, or perhaps google...
With those two in place, following a walkthrough (to get you used to using the development environment) will have you pretty much ready - you'll be able to look up what you want to say (reference), and know how to say it (syntax).
This, of course, applies principally to procedural/oop languages; languages that require a paradigm switch (ML/Haskell) you should go to lectures for ;)
(and for the weirder moments, there's SO!)
In the past my favour was "learning by doing". So e.g. I know a little bit of C++ and a lot of C#.Net but I must write a FTP Tool in Python.
So I sit for an hour and so the syntax differences by a tutorial, than I develop the form itself and look at the generated code. Then I search a open source Python FTP Client and get pieces of code (Not copy and paste, write it self to see, feel and remember the code!)
After a few hours I get it.
So: The mix is the best. A book, a piece of good code, the willing to learn and a free night with much coffee.
At the risk of sounding cheesy, I would start with the language's website tutorial and/or FAQ, followed by asking more specific questions here. SO is my centralized location for programming knowledge.
I remember when I learned Perl. I was asked to modify some Perl code at work and I'd never seen the language before. I had experience with several other languages, however, so it wasn't hard to figure out the syntax with the online Perl docs in one window and the code in another, side-by-side. I don't know that solely reading existing code is necessarily the best way to learn. In my case, I didn't know Perl but I could tell that the person who originally wrote the code didn't know Perl either. I'm not sure I could've distinguished between good Perl and really confusing Perl. It would've been nice to be able to ask questions here at the time.
Language isn't important. What is important is learning your ways around designing algorithms and the proper application of design patterns. Focus on the technique, not the language that implements a certain technique. Once you understand the proper development techniques, any programming language will just become real easy, no matter how obscure they are...
When you put a focus on a language, you're restricting your own knowledge.
http://devcheatsheet.com/ seems to be a step in the right direction: it aggregates cheat sheets/quick references and they are (somewhat) manually reviewed. It's also wide-ranging. It still comes up short a bit in terms of "idiomatic" quick reference: for example, the page on Ruby doesn't mention yield.
Rosetta Code appears to be an excellent resource that includes hints on coding idiomatically and moves from simple (like for-loops) to things like drawing. I haven't checked out how comprehensive it is, but there are a large number of languages and tasks listed. The drawbacks re: original question are:
Some of the linking is not accurate
(navigating Python->ForLoop will
take you to the top of the ForLoop
page, not the Python section). It's a
wiki, this can be improved.
Ideally you could "slice" the wiki
however you chose to see e.g. the top
20 tasks for two languages
side-by-side.
http://hyperpolyglot.org/ seems to be an almost perfect match for what I was looking for. The quality is not always there, or idiom can be lacking, but it has the same intention and is pretty comprehensive.
Does anybody know of any research or benchmarks of how long it takes to develop the same application in a variety of languages? Really I'm looking for Java vs. C++ but any comparisons would be useful. I have the feeling there is a section in Code Complete about this but my copy is at work.
Edit:
There are a lot of interesting answers to this question but it seems like there is a lack of really good research. I have made a proposal over at meta about this problem.
Pratt & Whitney, purveyors of jet engines for civilian and military applications, did a study on this many years ago, without actually intending to do the study.
They went on the same metrics kick everyone else went on in the 1990s. They collected a bunch of data about their jet engine controller projects, including timecard data. They crunched it. The poor sap who got to crunch the data noticed something in the results: the military projects uniformly had twice the programmer productivity and one/fourth the defect density as the civilian projects.
This, by itself, is significant. It means you only need half as many programmers, and you aren't going to spend quite as much time fixing bugs. What is even more important is that this was an apples-to-apples comparison. A jet engine controller is a jet engine controller.
He then went looking for candidate explanations. All of the usual candidates: individual experience, team size, toolsets, software processes, requirements stability, everything, were trotted out, and they were ruled out when it was seen that the story on those items was uniformly the same on both sides of the aisle. At the end of the day, only one statistically significant difference showed up.
The civilian projects were written in every language you could think of. The military projects were all written in Ada.
IN EVERY SINGLE CASE, against every other comer, for jet engine controllers at Pratt & Whitney, using Ada gave double the productivity and one/fourth the defect density.
I know what the flying code monkeys are going to say. "You can do good work in any language." In theory, that's true. In practice, however, it appears that, at least at Pratt & Whitney, language made a difference.
Last I heard about this, Pratt & Whitney upper management decreed that ALL jet engine controller projects would be done in Ada.
No, I don't have a citation. No paper was ever written. My source on this story was the poor sap who crunched the numbers. Here's a similar study from 1995:
http://archive.adaic.com/intro/ada-vs-c/cada_art.html
This, incidentally, was BEFORE Boeing did the 777, and BEFORE the 777 brake subcontractor story happened. But that's another story.
One of the few funded scientific studies that I'm aware of on cross-language productivity, from the early 90s, funded by ARPA and the ONR,
Haskell vs. Ada Vs. C++ vs Awk vs ... An Experiment in Software Prototyping Productivity, Hudak & Jones, 1994.
We describe the results of an
experiment in which several
conventional programming languages,
together with the functional language
Haskell, were used to prototype a
Naval Surface Warfare Center (NSWC)
requirement for a Geometric Region
Server. The resulting programs and
development metrics were reviewed by a
committee chosen by the Navy. The
results indicate that the Haskell
prototype took significantly less time
to develop and was considerably more
concise and easier to understand than
the..
This article(a pdf) has some benchmarks (note that it's from 2000) between C, C++, Perl, Java, Perl, Python, Rexx and Tcl.
Some common wisdom I believe holds true (also somewhere within the article):
The number of lines written per hour is independent of the language
Opinion: more important is what is faster for a given developer, for example yourself. What you are used to, will usually be faster. If you are used to 20 years of C++ pitfalls and never skip an uninitialized variable, that will be faster than Java for anybody.
If you remember all parameters of CreateWindowEx() by heart, it will be faster than MFC or winforms.
A couple of anecdotal data points:
On Project Euler, which invites programming solutions to mathematical problems,
the shortest solutions are almost invariably written in J or K, a relative of APL; there are occasionally MatLab solutions in the same range. It can be argued, though, that these languages specialized in math.
runners up were Ruby solutions. A lot of algorithm can be wrapped in very little code, and it's much more legible than J / K.
Python and Haskell solutions also did very well, LOC-wise.
The question asked about "fastest development," not "shortest code." But it's conceivable that shorter solutions are faster to come up with - certainly for slow typists!
There's an annual competition among roboticists. Contestants are given some specs for some hardware, a practical problem to solve in software, and limited time to do so. Again very domain specific, of course. Programmers have their choice of tools, including language of course. Every year, the winning team (often a single person) used Forth.
This admittedly limited sample suggests that "development speed" and "effect of language on speed" is often very dependent on the problem domain.
See also
Are there statistical studies that indicates that Python is "more productive"?
for some discussions about this kind of question.
It would make more sense to benchmark the programmers, not the languages. The time to write a program in any mainstream language depends more on the ability of the programmer in that language than on qualities of that specific language.
I think most benchmarks and statements on this topic will mean very little.
Benchmarks can always be gamed; see the history of "Pet Store".
A language that's good at solving one kind of problem might not apply as well to another.
What matters most is the skill of your team, its knowledge of a particular technology, and how well you know the domain you're trying to solve.
UPDATE: Control software for jet engines and helicopters is a very specialized subset of computing problems. It's characterized by very rigorous, complete, detailed specs and QA that means the multi-million dollar aircraft cannot crash.
I can second the (very good) citation by John Strohm of Pratt & Whitney control software written in Ada. The control software for Kaman helicopters sold to Australia was also written in Ada.
But this does not lead to the conclusion that if you decided to write your next web site in Ada that you'd have higher productivity and fewer defects than you would if you chose C# or Java or Python or Ruby. All languages are not equally good in all problem domains.
Language/framework comparison for web applications
The Plat_Forms project provides some information of this type for web applications.
There are three studies with different tasks (done in 2007, 2011, 2012), all of the following format: Several teams of three professional developers implemented the same application under controlled conditions within two days.
It covers Java, Perl, PHP, and Ruby and has multiple teams for each language.
The evaluation reports much more than only development time.
Findings of iteration one for instance included
that experience with the language and framework appeared to be more relevant than what that framework was.
that Java tended to induce teams to make laborious constructions while Perl induced them to make pragmatic (and quite handy) constructions.
Findings of iteration two included
that Ruby on Rails was more productive in this type of project (which due to its duration was more rapid prototyping than full-blown development of a mature application)
and that the one exception to the above rule was the one team using Symfony, a PHP framework that has similar concepts to Ruby on Rails (but still the very different base language underneath it).
Look under http://www.plat-forms.org or search the web for "Plat_Forms".
There is plenty more detail in the reports, in particular the thick techreport on iteration 1.
Most programs have to interface with some other framework. It tends to be a good idea to pick the language that has libraries specifically for what you are trying to do. For instance are you trying to build a distributed redundant messaging system? If so I would use Erlang. Are you trying to make a quick and dirty data driven website, use Ruby and Rails. You get the idea. Real time DirectX where performance is key, C++/C/Asm.
If you are writing something that is algorithm based I would look to a functional language like Haskell, although it has a very high learning curve.
This question is a little old fashioned. Focusing on development time solely based on the choice of language is of limited value. There are so many other factors that have equal or more impact than the language itself:
The libraries or frameworks available / used.
The level of quality required (ie. defect count).
The type of application (eg. GUI, server, driver etc...)
The level of maintainability required.
Developer experience in the language.
The platform or OS the application is built on.
As an example, many would say Java is the better choice over C++ to build enterprise (line of business) applications. This is not normally because of the language itself, but instead it is perceived that Java has better (or more mature) web server and database frameworks available to it. This may or may not be true, but that is beside the point.
You may even find that the building an application using the same language on different operating systems or platforms gives greatly differing development time. For example using C++ on Linux to build a GUI application may take longer than a Windows based GUI application using C++ because of less extensive and mature GUI libraries avaialble on Linux (once again this is debatable).
According to Norvig, Lutz Prechelt published just such an article in the October 1999 CACM: "Comparing Java vs. C/C++ Efficiency Issues to Interpersonal Issues".
Norvig includes a link to that article. Unfortunately, the ACM, despite having a bitmap graphic proclaiming their goal of "Advancing Computing as a Science & Profession", couldn't figure out how to maintain stable links on their webpage, so it's just a 404 now. Perhaps your local library could help you out.
That Ada story might be an embellished version of this: http://www.adaic.com/whyada/ada-vs-c/cada_art.html
Erlang vs C++/Corba
"... As the Erlang DCC is less than a quarter of the size of a similar C++/CORBA implementation, the product development in Erlang should be fast, and the code maintainable. We conclude that Erlang and associated libraries are suitable for the rapid development of maintainable and highly reliable distributed products."
Paper here
There's a reason why there are no real comparisons in that aspect, except for anecdotal evidence (which can be found in favor of almost any language).
Actually writing code takes relatively small portion of developer's time. Even if language lets you cut coding time in half, it will be barely noticeable by the time project ends. Design, structure of program, development process are all much more important, and then there are libraries, tools and experience with them.
Some languages are better suited for certain development processes than the others, so if you've settled on design and process you can decide which language will be more efficient - but not before.
(didn't notice there's a similar answer already, so feel free to ignore this)