welche

Welche is a German interrogative determiner and relative pronoun used to ask about or specify items within a defined set. It inflects for gender, number, and case. The form 'welche' appears in feminine singular (nominative and accusative) and in plural (nominative and accusative). Other forms include 'welcher' (masculine singular nominative) and 'welches' (neuter singular nominative and accusative); the remaining cases have corresponding inflections such as 'welchen', 'welchen', and 'welchem' depending on gender and number.

Usage and function examples include both questioning and linking clauses. As an interrogative determiner, it accompanies a noun: 'Welche Farbe hat dein Auto?' (Which color is your car?), or 'Welche Bücher hast du gelesen?' (Which books did you read?). As a relative pronoun, it introduces a relative clause: 'Die Farbe, welche du gewählt hast, gefällt mir.' In everyday speech, speakers often substitute 'die/der/das' for 'welche' in relative clauses, but 'welche' remains common in formal or written German. 'Welche' can also stand alone as a pronoun: 'Welche habe ich?' meaning 'Which ones do I have?'

Etymology and related forms: 'welche' derives from the Germanic interrogative base wel- and is cognate with English 'which' and Dutch 'welke'. It shares roots with other forms such as 'welcher', 'welches', and 'welchen', reflecting gender and case agreement in German grammar.

In summary, welche functions as a versatile tool for selecting or identifying items within a known set, with distinct forms across gender, number, and case.