Just as I suspected. In any case, Leafoosish isn't French proper, it's a dialect of Old French that has been heavily influenced by Cymraeg y cathod, so the rules of modern French don't apply here.

I just finished translating the Tower of Babel, so here it is:
1. E afa le fond antier yn lang e li fim mo.
2. E gan feiasean-aill dell est, truferan-aill yn seam an la der de Sinar, e fiferan aill lâ.
3. E dditeran-aill li yn ell ewtir, »Fenon, ffabricon dill fraic, e gwison-li fen.« E aferan aill bric pur pier e fitym pur mortier.
4. Pys diteran-aill, »Fenon, bastison-nu yn sitedd e yn tur con son some ddan li cil, e fabricon-nu yn nom pur nusewtir, an ca som dispersedd nu syr tut la der.«
5. E fen an ba le Senyr pur feir le sitedd e la dur ce aferan bastidd li enffen dill hymin.
6. E ddirith le Senyr, »Regard, son-aill yn pwple, e on-aill tut yn lang, e e'se swlman le gomansman de se ge feron-aill. E sera fentenan ren ce broposeran-aill â fêr emposible. Fenon, alon-nu an ba e lâ gonfyson-nu lwr lang, pur ce ne gomprendron-aill ren li yn li ewtir.«
7. Donc dispersa le Senyr li dde lâ syr tut la der, e aresteran-aill de fastir le sitedd.
8. Pur sâ es son nom Babel, pars ce lâ ddispersa le Senyr li syr tut la der.

I just got through reading part of my English Old French book (the one that's written in English -- couldn't find the French one), and I'll need to fix a couple of things but other than that Leafoosish is in pretty fine shape. I'll post the list of sound changes from le français des chats here, in case anyone feels like telling me if they're plausible.

Le français des chats is a dialect of Old French that is somewhat analogous to Cymraeg y cathod. However, unlike Cymraeg y cathod, it is considered to be extinct, and very little writing has been found in it. It is thought to have developed parallel to standard OFr, but it had a few fairly strange spelling conventions, such as the use of <w> that we have seen. It also retained all instances of ei that became oi in the humans' French.

Nuts, I guess everyone gave up on this thread. I can't blame you, because things have really been going nowhere here. In case anyone is actually still interested in Leafoosish, I wrote an article about it for my website. The link points to the English version, but it's also in French and I'm planning to translate it into Leafoosish and Tikolmian. I'd also like to translate it into another natlang, but I don't know any others well enough at the moment.

I guess everyone's out watching the Olympics. Anyway, I thought I should update this thread a bit for the sake of everyone who isn't following the "discussion" over on Unilang.
1) The [ɮ] sound isn't used anymore for the soft mutation of <ll>. Instead, we have [l] <l>.
2) The genitive construction is formed by putting the possessor after the possession. No articles are allowed before the possession so as not to cause confusion. The definite/indefinite distinction is made for the possession with the soft mutation; definite possessions are mutated and indefinite ones aren't. Never mind the words that can't mutate, they apparently don't matter.
3) There may be something called a vocative that's marked with the soft mutation.
4) Leafoosish seems to have 4 words for "door"; yfw, port, wis and dor. (The issue is with the last one -- it may be of English origin only and if so I'll have to get rid of it.) There are also two words for "fire"; ffw and tan. I'll get into this stuff in more detail later if somebody asks.
5) There's some controversy over what feminine nouns do. I think the general idea is that they get soft mutated and cause stuff following them to do the same, and masculine nouns don't do any of that.
6) We can't figure out how the present tense works.
7) <dd> is now written <dh>.
8) I should be in bed.

This is correct, but the last word should be written dôr to distinguish it from dor "gold".

The latter word should be written tân to distinguish it from tan "very, many, much". (Incidentally, circumflexed vowels are always lengthened as well, so there is a distinction in speech as well as in writing.)

If no one objects, I'm going to periodically post corrections and updates here just so nobody gets left out of the loop.

Everything up to the bolded text is correct. There's never any mutation on the possession unless it follows a word in another clause that triggers it. If you really need to specify that the possession is indefinite, then you use de "of" (this is similar to the Welsh use of o with the same meaning). If you feel the need to specify plurality as well, then you can use tus "all [of]" in front of the possession. This does not trigger any mutation.

I think not.

That's correct. The feminine definite article la triggers the soft mutation, and any adjectives or whatever following feminine nouns have to agree in mutation (I think).

Still can't. There's a preference for the "progressive", but I couldn't settle on a satisfactory way of marking it.

It is.

Not anymore, it's morning! I have to wake up and smell the roses now.

As of 11/09/12, <w> is used for all instances of /u/; I was having serious trouble putting up with the redundancy of the earlier spellings. As far as <u>, it's used for /ɨ/ -- usually in unstressed positions, but you'll find a few stressed ones as well. <y> is now /ɪ/ or /ə/; the former is when stressed and the latter is when unstressed. It should be the only way of spelling /ə/ at this point, so former "weak" e's are now written <y> (except in final position, where they've been lost from the pronunciation and often the spelling of most dialects; e.g., ofrase [ɔv'raʃ] or ffenestr [fɛ'nɛst]).

I still haven't figured out whether Leafoosish would use <v> or not. I did a little research on <v> in Welsh but to no avail. In other words, it didn't really help me figure out anything about Leafoosish. I'll be sticking the dictionary up online soon, but it'll take a lot of work because lots of stuff needs to be ironed out still.

I've heard "faire du sense" as in making sense. Or as in "Ça ne fait aucun de sense". Apparently, it is an anglicism[0], and the 'correct' way would be to say "avoir du sense".

[0] http://66.46.185.79/bdl/gabarit_bdl.asp?id=3499



EDIT: I'm really sorry, I just realised I replyied something really old in the thread. Nice language, BTW!