One of the toughest things to do in writing fiction, IMO (no H involved), is to write dialogue. Too often we try to make it sound real and end up making it sound strange. This is especially true when we try to write dialect or imitate a foreign language.
I once read a book that I couldn’t make sense of unless I read it aloud. Each character’s dialogue was written phonetically to represent their regional dialogue.
When my son was a preschooler, a big name New York author wrote a book set in the South. Her characters were all local and I know that she thought they truly sounded peachy. I think that I made it to all of about page 15 before I just couldn’t take it.
The same thing happened when a headline actress tried to imitate a North Carolina accent. I swear. My ears bled.
My daddy grew up in Texas and I was born there. Grand-dad is from Mississippi. Then there’s my cousin’s husband from South Carolina, another cousin in Georgia, and a whole branch in Florida. I simply was not buying what they were selling and the worst thing was that they laid it on too thick.
How then do you make it work? Especially when you are writing for children, keep the dialogue understandable. If your character speaks a language or a dialect other than standard English (assuming here that you are writing in standard English), choose a few phrases to drop in every now and then. Maybe a greeting. Or an endearment. Or something they say when surprised.
Or use a grammar rule from their language to restructure a standard English sentence. A friend of mine from China used window and mirror interchangeably when she was tired. They are the same word in her dialect. Another group of friends used the pronouns his and her interchangeably. They did the same thing with he and she. Their language has only one word for his, her, she, he and it.
Whatever you choose to do to represent their language or dialect, use it sparingly, like a spice. You want to add a little flavor, not overwhelm the reader.