infixeja

Infixeja is a linguistic term used to describe the set of infixes—morphemes inserted inside a word rather than at its edges. The term appears in discussions of both natural languages and constructed languages and refers to internal morphemes that modify meaning, grammatical category, or word class. Infixeja thus covers a range of processes collectively known as infixation.

Infixeja differ from prefixes and suffixes in where and how they attach, often requiring specific phonological contexts. Traditionally, infixes insert after the initial consonant or syllable, and they may be derivational or inflectional. They can appear alone or alongside other affixes, producing complex word forms. Across languages, the frequency and distribution of infixes vary, with infixation being particularly characteristic of some Austronesian languages and relatively rare elsewhere, making it an important area of typological study.

A widely cited example comes from Tagalog, where the infix -um- is inserted after the first consonant to form new verbal forms, such as sulat (to write) becoming sumulat. Infixes can interact with phonological rules, causing consonant or vowel adjustments to preserve permissible sound sequences. Because infixes operate inside the word, they can be less transparent to listeners unfamiliar with the pattern, yet they illustrate the diversity of morphological strategies used by languages.

See also: infix, affix, morphology, Austronesian languages. The term infixeja itself is used in some grammars and conlangs to discuss the general phenomenon of internal affixation.