I am watching a Japanese movie and I noticed also in other places and during my visits to Japan some people say: arimas, des. Others say: arimasuh, desuh
Does it have to do with different regions of Japan or with a certain act of politeness (trying to speak clearly e.g for teachers). Even a Japanese friend could not answer this question as she does not seem to notice the difference.
To help you a bit in your search: this phenomenon is called vowel devoicing. From what I understand, devoicing happens to γ§γ in most dialects of Japanese. People will occasionally voice these vowels for emphasis or comedic effect or etc.
Iβm not particularly familiar with Japanese dialects, so I canβt say for certain if some dialects opt for voicing the ending γ by default, but as far as Tokyo dialect goes, itβs pretty generally dropped.
βOther vowels can be devoiced, but this occurs much less frequently. On the other hand, fully pronouncing vowels that would normally be devoiced is sometimes heard in certain female speech, formal speech, and some western dialects.β