Not the same way as nouns or adjectives have. Some verbs have two versions of them and usually the -ella/-ellä ending makes the verb less attentive or less serious, or more specific: haistaa vs. haistella = to smell something, first one is the action of smelling something overall and the second one is smelling something specific. Same with: katsoa vs. katsella = to watch; you can "katsoa" and "katsella" a movie, latter just is less attentive. I think Finns just got bored with a same word meaning too many things and they created endings to be able to tell what exactly they are doing :D This -ella/-ellä version seems to mainly happen with verbs containing -st- or -ts- in them.
In a way that sometimes also feels like it's bit like -ing ending in English, except that it still is not a continuous form and cannot added to just any verb. So basically: haistaa = to smell something, haistella = to be smelling something; but in Finnish they are different words rather than different tenses of one word, and you can still say "I'm smelling smoke in the air" in English and translate that as "Haistan savua ilmassa." because "Haistelen savua ilmassa." means that you're in the middle of the action of, well, sniffing the smell of smoke which is in the air.
With all these "haistaa" verbs etc. the core word is 'haju' = 'smell'. But then there's also this one: "hajustaa" which means that you add a perfume to something to cause it to smell different. (And also for comparison: grammatically "hajuttaa" is also possible, but it does not mean anything in Finnish.)
I see one can also make nouns into verbs with similar suffix, -stella/-stellä but the consonant after the s changes to whatever suits the noun the best. In theory you can make any noun into a verb with this but majority of them would just sound like nonsense. (Finns love to flex with the fact we can create an indefinite amount of new words just with all the possible suffixes but in the end no one is ever going to use even majority of those :D Bit like when you can make insanely long words in German but which no one will ever use in real life.)
Yes, that's true. I don't like the English verb too much because in Finnish there's three different versions for that word only :D
- haistella (jotakin) = to smell something, like roses like you said in your other comment.
- haistaa (jotakin) = to smell something but like, in the air. E.g. "Haistan savua." is "I smell smoke."
- haista (joltakin) = to smell like something
So every time I use the word "smell" in English, I feel like I'm saying something wrong even when I'm using the correct prepositions/words with it or leaving them out when not needed. And the two latter ones are usually used when something smells bad or weird, "tuoksua" then is about good odours (but only as "tuoksua joltakin", or if it's in the air, "Täällä tuoksuu (joltakin)." Which is another reason why the word "smell" always makes me feel a bit weird.