Full Idea
The now famous Piraha language, of the Amazon region in Brazil, allegedly has no number words.
Gist of Idea
The Amazonian Piraha language is said to have no number words
Source
Thomas Hofweber (Ontology and the Ambitions of Metaphysics [2016], 05.6)
Book Reference
Hofweber,Thomas: 'Ontology and the Ambitions of Metaphysics' [OUP 2018], p.149
A Reaction
Two groups can be shown to be of equal cardinality, by one-to-one matching rather than by counting. They could get by using 'equals' (and maybe unequally bigger and unequally smaller), and intuitive feelings for sizes of groups.