The plain and simple fact, which *nobody* here has brought yet, is that any language which is adopted by Jews (for Torah) becomes a language of kedusho. Yiddish is only used by Jews, nowadays almost exclusively by chareidim (and a few elderly secular Russians). Therefore, it does have an added kedushah which a language such as Chinese or Japanese lacks.
Whether Lakewood English (Yeshivish) has the same level of kedushah, I don’t know.
I myself speak, understand and read Yiddish very well, but unfortunately I cannot really write it. Unfortunately, many people – even chareidim – who speak Yiddish have lost the capability to write it.