Translation:I speak the language that forests and bogs speak.
Puhua is usually used with the partitive case (which makes sense, as one always speaks some of a language and doesn't consume all of the language by speaking it).
Note that the ä in kieltä is not an accent. Ä is an altogether different letter than a. It's the penultimate one in the Finnish alphabet.
Normally you should be able to add alternative keyboard configurations both to computer and phone keyboards. I swap between an English and a Swedish keyboard layout on my work laptop and between a Swedish and Russian on here on my phone, with the touch of a button or two. Check out the language options on your device.
Duolingo generally allows for one spelling mistake per answer. So if you have an answer with two ä's or ö's... I don't really know how else you can solve that.
It doesn't really, that I know of or could find right now. It's not the same as in German where there actually seems to be a debate as to how many distinct letters of the alphabet there are or what the correct place of those letters with an Umlaut is in the alphabet. Or in French and Dutch where the point of the diaeresis is to guide pronunciation, and actually keep the sound as it is rather than merging it with a neighbouring one. These are truly separate letters in Finnish, which happen to be written like this.
Of course you can describe them as dots, but that's not a technical description. One way of referring to the letters themselves is skandinaaviset kirjaimet, which is however slightly confusing since they are used also in languages other than the Scandinavian languages + Finnish. Finally, a humorous and quite common term which definitely isn't technical is calling those letters ääkköset, a word play on aakkoset, the alphabet.
An 'umlaut' would be the best discription as it shares history and purpose with the German 'ä'. It started as an 'a' with a small 'e' above it to denote a vowel-sound somewhere between 'a' and 'e'; slowly the 'e' became two dots.
In Scandinavia both 'æ' and the German styled 'ä' were used for this purpose, but after Sweden left the Kalmar Union, 'æ' became the most popular in Denmark-Norway and 'ä' most popular in Sweden. Finland of course uses the Swedish alphabet.
Kuulitko ¤suden(the wolf's) ¤ulvovan(howl-ing at) sinistä kuuta? Näitkö ¤ilveksen(the lynx's action or trait being observed, so ownership form) ¤hymyilevän(smiling).
If you want to use "sutta", you have to do it like this: "Kuuletko sutta, kun se ulvoo sinistä kuuta?" (Can you hear the wolf as it howls for the blue moon?"
If you want to use "ilvestä", like this: "Näetkö ilvestä, kun se hymyilee?" (Can you see the lynx when/as it smiles?)
Don't worry, if you want a challenge, Finnish is a perfect choice. Fun stuff like that only an agglutanative language can do like:
Koira / A dog || Koirani / My dog || Koirasta / From a dog || Koirastani / From my dog || Koirastaniko? / Really? From my dog? || Koirastanikaan / Not even from my dog || Koirastammekaan / Not even from our dog.
This works from any noun and those are singular. Then there's the plural forms... which i won't type now as i'm getting close to work time.
Finnish would be difficult grammatically alone, but then there's the dialects. :)
For example this is the language where these 2 quotes have the exact same short story with nothing added or removed:
"Ämmäkkim meni saunaha emoilemmaa, kinnisteli ja punnisteli kaikem päivää saunassa, mutta minä menin saunaan ehtoolla ja sam poika et tuup sie kattoommahan ja poika tuli että pulpahti."
"Vaimonikin meni saunaan synnyttämään. Hän ähisi ja punnisti koko päivän siellä. Itse kun menin sitten saunaan illalla, niin poikani pyysi minua tarkistamaan tilannetta. Silloin totesin, että olin saanut uuden pojan."