A map of insufficient gram length should produce a warning

[Jeroen T. Vermeulen]

If you run langmatch at a gram length of n, and one of your language maps only goes to gram length m where m < n, you're not likely to get a good match even if the language map represents exactly the right language. (If m > n, the longer grams will be ignored which is fine).

There should at least be a warning about language maps of insufficient gram length.