Speakers of Tetun Dili, in Timor-Leste, commonly use three sets of numerals, namely native Tetun as well as numerals from the languages of the two former colonial powers, Portuguese and Indonesian. Tetun numerals can modify nouns from any language, within native Tetun constructions. In contrast, borrowed numerals modify only nouns from the same source language, using source language order. Functional and sociolinguistic differences were sought based on an extensive corpus of texts as well as two surveys of numeral use. The choice of numeral language is complex. Contributing factors include the language of the head noun for attributive adjectives, the size of the number, the topic, and sociolinguistic factors such as formality, lectal type, and language of education of the speaker and of the preceding generation. Tetun numerals are primarily used for small numbers within traditional contexts, while Indonesian and Portuguese vie for position for larger numbers and modern contexts.