PolyglotKeyboard!

Uosk is a light tool that opens any ASCII, ANSI, UTF-8 and UTF-16 text file and converts words (e.g. separated by spaces) into buttons. Clicking one button the text snippet is pasted into any text editor (Notepad, WordPad, MS Office, OpenOffice...). You can edit snippets directly in Uosk, and save them as a new txt file. The snippet can also be copied to clipboard.It's basically a virtual keyboard with ability to set any amount of characters in one button.

With keyboards for over 1000 languages, Keyman Desktop lets you type in your language even when Windows doesn't. You can even create your own custom keyboards with Keyman Developer 9.0. The free version offers 2 languages.

Sellinam enables Tamil text input on mobile devices. It suports Tamil phonetic keyboard too. It was first developed in the year 2003 and subsequently launched for public usage in 2005 on Ponggal day.