Another important factor in regards to their relationship with other races would be their possible predisposition for spreading disease.
In times of scarcity due to overpopulation, civil conflict, natural disasters, and so on, it's quite likely that many mosquitofolk would resort to drinking blood from the livestock of neighboring races to survive. At first glance, this wouldn't be too big of an issue, it's not like cows can't afford to lose a bit of blood, except when you consider the fact that blood-drinking animals like mosquitos are a massive vector for all kinds of nasty zoonotic diseases. Normally, large animals aren't affected by mosquito-born diseases, but given how much larger and more dangerous the microbiology of a mosquitoperson would be, they could spread outbreaks in livestock populations very easily, which could then spread to the sapient populace through the consumption of infected animals. This would naturally cause other races to view mosquitofolk as an existential threat to their food supply. It would also allow opportunities for biological warfare, either as a defense mechanism or as mercenaries.
They would essentially be flying vermen, only more remote and thus harder to dislodge.
In regards to the language barrier, a writing system could make up for some of that, though communication would still be very difficult and clunky.