Frankfurt is indeed the spur. I'm still fighting Finnish participles and have now bought Books 3 and 4, to supplement the other two. My problem with the participles is twofold. a) it's hard to remember which vowels you leave out, and which consonants are doubled or not or mutated, depending on which root you are starting from; and b) the inefficiency, syllables versus meaning, of such particles in the oblique cases.
I've actually translated a story from Finnish now, and sent it to the author for approval. I feel that she was pretty positive about most of it. I had, of course, misunderstood things here and there, but as a whole I think I've succeeded. I didn't notice a surfeit of participles there.
One problem I have is interference between Estonian and Finnish. This rarely occurs when the text is in front of me on the page, even though "ilu", "raamat", "linn", "vaim", and "hilja" are not the same as "ilo", "Raamattu", "linna", "vaimo" and "hiljaa". There are quite a few faux amis between the two languages. If I try to speak, i.e. generate a grammatical sentence in either language, I start throwing in things from the other one. This can lead to confusion. Muidugi, I mean tietysti. Unfortunately, I cannot quite shut off one altogether and concentrate on the other. I translate from one and I'm learning the other. People have the same problems with Spanish and Portuguese, Dutch and German, Russian and Polish, and so on. Only people such as the Hungarians and Basques are fairly safe from faux amis, as no one else on Earth speaks like they do.