All words begin with a root morpheme to which other morphemes are suffixed. Agglutinative languages tend to create very long words with derivational morphemes. The main difference between derivational morphemes and inflectional morphemes is their function for words. Compounds may or may not require the use of derivational morphemes also. However, they often are listed on the basis of their derivational morphemes. The term "allomorph" explains the comprehension of phonological variations for specific morphemes. Chinese morphemes, or minimum units of meaning, are mostly monosyllabic. Most such words are compounds, but some are single morphemes (generally loanwords). Hmong is an isolating language in which most morphemes are monosyllables. The reason is that possessive adjectives are system morphemes. Sentences in analytic languages are composed of independent root morphemes. A Matrix Language island is a constituent composed entirely of Matrix Language morphemes. See polysyllabic Chinese morphemes for further discussion. Polysynthetic languages, such as Chukchi, have words composed of many morphemes. The Quechuan languages have three different morphemes that mark evidentiality.