Maya books provided the key to deciphering Maya writing. Most of the texts are short and are accompanied by images. Since word order in Mayan languages is verb-object-subject, it is often easy to infer the grammatical function of particular glyphs. Three of the four surviving books can be placed by their style in northern Yucatan in the last few centuries before the Spanish invasion, so the language of the composers was almost certainly Yucatec.

The writing system in the books developed on the basis of earlier writing systems used to record one or another Mayan language over the preceding 1500 years. It is essentially a script for recording Yucatec, though some of the content, at least of the Dresden Codex, seems to have been adapted from earlier texts and may record Cholan linguistic forms.

Most of the signs used in the script are either morpheme signs (representing units of meaning, word roots) or phonetic signs (most or all of which represent consonant-vowel (CV) syllables). Some signs, especially deity names, appear to be emblematic, essentially logograms (word signs). A few signs may mark particular grammatical functions. Many signs have multiple values, representing words, morphemes, or phonetic values in different contexts. Conversely, the same morphemes and phonetic values can be represented by more than one sign.

Kawak polyvalence

Phonetic signs are used alone to spell entire words; as phonetic indicators (in Whittaker's sense), clarifying the referent of a morpheme sign; as phonetic complements, adding to what is specified by a morpheme sign. Since most morphemes in most Mayan languages have the form CVC, when they are spelled with phonetic signs representing syllables, the final vowel is not pronounced.

Ketunnen syllabary 1