[ang_cire]

In Japanese, yes, because it has a phonetic alphabet. For example, "konnichiwa" is often shortened as "kon'chiwa".

In Chinese, there is shorthand slang, but not shortening of words in writing based on spoken sounds (since it's not phonetic).

So even if "wo shi" (I am) might be spoken more quickly, there's no way to write that shortened version out in Chinese. You will actually see Chinese speakers use Latin characters and Arabic numerals for phonetic shorthand, (e.g. '88' for "bye bye", because 8 is pronounced 'ba'/'bai'.