Stative verbs in English include those showing senses (hear, see, smell, feel) are generally not used in a continuous tense. When they are used in a continuous tense, it can actually change the meaning. https://www.thoughtco.com/differences-between-action-and-stative-verbs-1211141 Consider:
- the pig smells the wild mushroom (the pig has a sensory awareness of the scent of the mushroom)
the pig is smelling the wild mushroom. Here, the verb in a continuous tense is an action verb and depicts that the pig is actively smelling the mushroom. I.e., the mushroom is right there in front of the pig and he is seen to sniff it (he is smelling it).
I smell flowers. (I detect the scent of flowers in the air).
- I am smelling flowers. I am actively/deliberately engaged in smelling flowers (because I enjoy their scent).
2018-05-17 Perhaps in this case, "wild mushroom" refers to truffles, which traditionally were found using hogs to sniff them out. This sentence could then be a general statement, like one in a documentary film.
A truffle is "une truffe". Here, we can only be certain that they are mushrooms growing in the wild, i.e., not farm-grown.
Because it's a singular. "Smells mushroom" is not a common English expression to my knowledge.
The English translation is unnatural. The English translation would use mushrooms in the plural. "The pig smells the wild mushrooms."