On this side of the pond, we have different types of grasshoppers, crickets, and katydids... and the katydids are so named because their song sounds like they are saying, "katydid, katydid" or "katy-she-did, katy-she-did-she-did"!
Tree Cricket Pictures and Songs
common true katydid (Pterophylla camellifolia)
Both of the above links include some photos and wav recordings of grasshopper and katydid songs. Enjoy!