Have you not forsoken...?
What's neat is that you don't have to specify the language for it to start conjugating, and it'll ask you to disambiguate verbs spelled identically in supported languages. Plus, if it doesn't recognise the verb at all you can specify the language and ask it to "conjugate as regular". Funny thing, though, was when I put in the verb "forsake" (not sure if the link will work; if it doesn't, click here and type in "forsake" yourself). wondering what it'd say the past tense was. Hmm..."I forsoke, you forsoke..."? "I have forsoken, you have forsoken"??? Methinks there's a bit of over-generalisation going on here from the verb "wake".
I still remember very clearly arguing with an English teacher in primary school about the past tense of that verb. I said it was "forsook", can't remember what she thought it was but she marked it as wrong. Grrr. Anyway the web agrees with me: look at the hit counts below. Mindful of the recent Language Log posts about the inaccuracy of Google's counts, I got the Yahoo! ones as well:
Google Google restricted to English Yahoo! Yahoo! English
forsaked 729 3,460 1,300 1,250
forsook 201,000 169,000 168,000 167,000
forsought 44 41 18 16
forsoke 521 369 365 278
It should be noted though that it looks like "forsoke" was an old English spelling. So go back a few hundred years, before lexicographers started standardising orthography...and Universal Conjugator would've been right. Oh, and another thing - their Arabic conjugator needs a lot of work.