Et j'espère que tu me pardonneras if I poke fun at your "consonnant length is significant in Finnish" as you accidentally misspelled "consonant" with too many consonants :-)

My understanding about Finnish and Estonian was rather that it was obvious that they are languages from the same family, but that they're not more mutually understandable than French and Italian would be. One of the differences is that writing and pronunciation have remained pretty rigid in the main Finnish (by opposition to the familiar/spoken versions), while Estonian has undergone some of the transformations you see in other languages (where sounds are approximated, or lost, like Going to > Gonna, Want to > Wanna).

If you want similar languages I would advise looking at Danish, Icelandic, Norwegian and Swedish. With Icelandic closer to the old Norse, and the last three being basically sister languages (:P). One of the funny things about Norwegian (well, one flavour of it), is that it has kept the Danish spelling of words even when the pronunciation matches Swedish more closely. So in some cases, it looks like Danish but sounds like Swedish :D .

Speaking of language trees, you can look at Minna Sundberg's work (well, that page specifically, but the whole comic is pretty good :) ). Where you can see that Finnish, isn't even on the same tree as other european languages :)

Edit: my friend in Finland just confirmed, it should be hymysi rather than just hymy (to have the "thy" meaning).