This code is given by Bharati Krsna in Chapter XXV of his book. It allows any Sanskrit text to be converted to numbers, or any Sanskrit text to be composed so that it describes a sequence of numbers.
Bharati Krsna says: 'It is a matter of historical interest to note that, in their mathematical writings, the ancient Sanskrit writers do not use figures (when big numbers are concerned) in their numerical notations but prefer to use the letters of the Sanskrit (Devanagari) alphabet to represent the various numbers! And this they do, not in order to conceal knowledge but in order to facilitate the recording of their arguments, and the derivation conclusions etc.'
The Key to the Code
'The very fact that the alphabetical code (as used by them for this purpose is in the natural order and can be immediately interpreted, is clear proof that the code language was resorted not for concealment but for greater ease in verification etc., and the key has also been given in its simplest form:
The vowels (not included in the above list) make no difference; and in conjunct consonants, the last consonant is alone to be counted.'
So if you want to describe the number 11 there are many choices: papa, tata, tapi for example.