If anyone's interested what a Finnish accent might sound like in English, I've found that they can't really say the "sh" sound, so you might hear them say "Engliss" or "Finiss". Also, they tend to pronounce the words "good", "book", and "look" in an extended, drawn out way, like "guud", "buuk", and "luuk". Just some interesting observations! Would love to hear more examples you've heard :)
The English w sound doesn't exist in Finnish, so Finnish speakers sometimes just pronounce it as a v, or mix these two sounds up a bit. For example saying "willage" instead of "village".
Some Finns don't really hear the difference between d and t, b and p, and g and k, as the former in each of these pairs does not really exist in Finnish words other than loan words. This leads to some people pronouncing or even writing words or names wrong.
The th sound in English, which is hard for many other non-native English speakers as well, often just becomes a plain t when pronounced by a Finn.
Also, many Finnish consonants aren't as strong (aspirated) as the English ones, so especially our t's and k's sound weak, e.g. "tap" sounds almost like "dap." The exception is r because we might use the Finnish rolling r instead. We also often fail to observe the difference between English vowels and use the closest Finnish one, such as want -> want/wont (it's usually older people who use this o version) and hut (hat), car (kaa(r)), over (ouver/ouvö). This is especially true with "ö" replacing the schwa sound. Sometimes when we do observe a difference, we might replace it with something else, for example hunt "hant" and haunt "haunt".
In addition, we tend to believe that words are better understood the way they are written even in English, so sometimes we pronounce words (especially rare or difficult words) as if they were Finnish, such as "poverti" (poverty) or "kuriositi" (curiosity). Some of us find it hard to believe that silent letters shouldn't be pronounced, such as the w in "write" or "sword" or b in "comb".
In all fairness, Finnish compounds rules can be quite harrowing. I'm a native speaker, and while I hate when careless native speakers make ‘ralli englanti’ type elementary compound mistakes, I virtually always manage to do a few mishaps myself with more complicated cases if I take a Finnish compound quiz online. There are a lot of edge cases and a plethora of exceptions.
Nope, this means that they are speaking a different language, but have a Finnish accent when doing so.
I've never heard or experienced more than one "Finnish accent" when hearing Finnish people speaking English, for example. Unless they are very good, you can hear they are from Finland, but you can't guess from which part of Finland. So only one accent.