Almost every developer/sales rep has been in the situation where the customer asks which programming language the product is written in. If your application is written in C#/VB.NET, running on .NET, you're fine. No further questions. But what if you have to answer "SAL, using Unify Team Developer"? Your customer will probably ask "Sal, what? Unify, who?". Many times this is already the end of the sales process and the potential customer is lost, no matter how good your application is. Gupta/Centura/Unify is simply not known and therefore not taken into consideration.
The more popular a language is the more it is accepted and the more chances you have to sell your application. But what exactly means "popular"? Well, there's a company that put some work into figuring this out and they came up with a list of languages that people search for most on popular search sites like Google, Yahoo, and others. Find the list at http://www.tiobe.com/index.php/content/paperinfo/tpci/index.html.
The list is ordered by the number of searches and the language being searched for the most is on top of the list. C and Java are the leaders. PHP is very popular too but I don't consider it a general purpose language because it is mainly used for web applications only. Visual Basic is still going strong but C# has made it's way up and will continue to increase market share.
On the list you can even find laguages like SAS, MATLAB and LUA which, to be honest, I had never heard of. There's outdated languages like LISP, COBOL, Fortran, Smalltalk and whatever else. A long list of 50 programming languages where the ones at the end of the list have an extremely low market share, they are absolute niche products.
So what about SAL/Team Developer? Not on the list. Nada. Niente. Non existent. It's not even a niche product! Being a SqlWindows developer myself since the 16-bit ages I moved away many many years ago and it turned out to be the right decision. At that time I had to rewrite from scratch because there was no migration tool but times have changed and now The Porting Project offers painless transition to modern platforms. Platforms that don't force you to explain what language you used and who Unify is. The Porting Project makes it easy to switch to a programming language that is widely accepted and that you can find in the top range of languages used by developers worldwide.