Cross-linguistic variation
Many Indo-European languages (the family that English belongs to) also use the equivalents of ‘have’ and ‘be’ as auxiliaries, as does the entirely unrelated European language Basque. But language don’t all use auxiliaries this way. As the quotation from Schechter pointed out, any grammatical category for verbs which in some language is realized (= displayed) on an auxiliary may be realized via an inflection on the main verb in some other language. For example, the Brazilian language Bare expresses both progressive and perfect aspect just by inflections on the main verb, with no auxiliary: