pronunciation - Pronouncing ない as ねい / ねえ (also ~oi to ~ei)

I noticed that in anime and other Japanese shows, people often pronounce 「ない」 as 「ねい」. For example, instead of saying 「使わない」, the person will say 「使わねい」, but the translation is the same.

I have many questions about this.

• Is there any nuanced difference in meaning between 〜ない and 〜ねい?


• Is it a colloquialism? Is it from a specific region or used mostly by one gender?


• When written, is it spelled 〜ねい or 〜ねえ? And do people often use it in writing, or only in speech?



• I've also noticed that 「すごい」 sometimes gets pronounced 「すげい」. Is this the same phenomenon? Are there other non-ない examples?


• Does this transformation have a name? I'd like to read more about it but I don't know what to search.

Answer

1. I see it most often spelled out as ねー as in 使わねー etc.


2. For me it has a rough, slightly negative, rude connotation (e.g. used by ruffians and ヤンキー, or the older generation that speak their opinions freely). It is also more prevalent in males than females.


3. I've seen ねー、ねえ、ねぇ but not ねい.


4. Can be used in the positive to show emphasis (also used by above) e.g. やりてぇー、食べてーetc etc.


5. If there is a name, I don't know it..