Integer to English challenge
intToEnglish(-1) returns "undefined", which might not be what you want. Same goes for fractional values, although I guess that case could be waved... if you only support integers. Even so, you might want to add a check. At the very least, add a comment - problem descriptions are kept separate from your code right now, and that makes it non-obvious that it doesn't support such things!

Negative numbers could be supported via prepending "minus", then translator(Math.abs(n)).