Any hints on how to translate the 'Nanny' in Totoro?

Question

I'm working through translating となりのトトロ and I was doing ok until the Nanny starts talking. Going through her sentences and translating them piece by piece is an exercise in extreme patience. I find her lines very confusing.

Is she speaking in a particular dialect that I can reference?

Here's an example sentence that confuses me:

ニコニコしとれば 悪さは　しねえし いつの間にか いねくなっちまうんだ。

Which I've translated literally to say:

If smile wet, as for the bad things they will die and leave completely before you notice, you see.

So, "If you keep smiling the bad things will go away."

But the details escape me. What's up with the wet smile for instance?

(It's about 15 minutes in, if you have the video...)

Answer 1

ニコニコしとれば 悪さは　しねえし いつの間にか いねくなっちまうんだ。

This is the same as the following sentence written in the standard Japanese.

ニコニコしていれば悪さはしないし、いつの間にかいなくなってしまうんだ。
If you keep smiling, they won't do bad things, and they go away before you notice.

The original sentence is not in a particular "dialect", but a typical role language of an old man/lady (aka 老人語).

• しとる is short for しておる, and おる is the same as いる in this context:
  • what does てはいる in this sentence mean?
  • おる in honorific contexts
• ない → ねえ, いなく → いねく:
  • Changing of diphthongs at the end of words to え in exclamations
  • What does the word 「ありゃしねえ」mean?
• てしまう → ちまう:
  • https://japanese.stackexchange.com/a/18159/5010

悪さをする is a set phrase meaning "to do bad things", "to cause mischief". The verb 死ぬ is not used here.