Male crickets use stridulation, rubbing specialized body parts together, to make their characteristic sounds.
A male cricket usually scrapes a ridged file on one forewing against a hardened scraper on the other. The wings act as vibrating surfaces, and their movement produces the familiar chirp. The exact pattern and pitch depend on the species, temperature and the structure of the wings. In many crickets, males call to attract females and may also signal during territorial encounters.
Stridulation is a broad biological mechanism, not a sound limited to crickets. Grasshoppers, katydids, beetles and some spiders can also produce sounds by rubbing body parts. That is why “chirping” is less precise than naming the mechanism.
Cricket song is also temperature-dependent: many species call faster as temperatures rise within a suitable range. However, the exact relationship differs among species and should not be treated as one universal formula.