Polysynthetic languages are languages where words consist of very many bound morphemes, such that a sentence can often be expressed in a single word.
Greenlandic, Navajo
Greenlandic example: Aliikkusersuillammassuaanerartassagaluarpaalli Morpheme breakdown: aliikku-sersu-i-llammas-sua-a-nerar-ta-ssa-galuar-paal-li Translation: However, they will say that he is a great entertainer, but …