Notes:

Inspired by this brilliant video (8:43):

For the record, I only included languages in which only the plural form of "apes" and "monkeys" is synonymous; this graph excludes languages in which the non-plural form of "apes" and "monkeys" is synonymous but not the plural (in German, for example, "affe" is used to refer to both monkeys and apes, but the plural form of those words are, respectively, "affen" and "menschenaffen").