I am not fully aware that no other languages are used for Numerological purposes.

I know only Indian - English and Tamil languages.

I am not an expert in any kind of linguistic history, statistical studies and knowledge.

My Numerological inspiration first started from reading Cheiro's Numerological English books.

I have not read any satisfactory justification on 'why only English language and alphabets are used for Numerology'.

But any names in any languages can be spelled in English Alphabets, as per the pronunciation or sound.

From my study and research, the value of that English Alphabets is having amazing influences on that particular name as well as on that particular person.

That's why, I am using English alphabets for my 
Name Segments.

You can check by yourselves, the Non-English names' value's influences, with our various Ready References.