approximant is written r. To those basic rules are added two adjustments to make the alphabet easier to use. The indicators y (for palatal) and r (for retroflex) are often dropped if they are redundant in consonant clusters with the same position of articulation: nyj is written nj, rnrt is written rnt. At the beginning of a word, the retroflex indicator r may be omitted. That does not produce ambiguity because no Warlpiri word begins with a plain alveolar consonant: 'foot' is written . Morphology Verbs Warlpiri verbs are built from a few hundred verb roots, distributed among five conjugation classes. Two of the classes contain the vast majority of verb roots; the other three classes have only a few roots each. A large class of modifying prefixes, or preverbs, are used to create verbs with specific meanings. For example, the verb root means 'run' by itself, and means 'scurry into hiding'. The preverb is used with a few other verb roots to form other verbs of hiding or seclusion. Preverbs are sometimes reduplicated for emphasis or to change the meaning. Most preverb-verb combinations are fixed in the lexicon, and new combinations cannot be created freely. However, a few preverbs are very productive and can be combined with many different roots, and some roots accept almost any preverb. The verb root is followed by a tense suffix. There are five of them for each conjugation class, as shown in the following table. (Some optional variations have been omitted.) Nouns Warlpiri nouns are assembled from thousands of roots, with a rich array of derivational techniques such as compounding and derivational suffixes. Plurals are formed by reduplication of the root. Auxiliary word and agreement suffixes Each full Warlpiri clause may contain an auxiliary word, which, together with the verb suffix, serves to identify tense and to clarify the relationship between main and dependent clauses. Common auxiliaries include (present tense), (future tense), (conditional). The auxiliary word is almost always the second word of a clause. The auxiliary word also functions as the home for an elaborate family of suffixes that specify the person and number of the subject and object of the clause. They are similar to the familiar conjugational suffixes that agree with the subject in Indo-European languages, but in Warlpiri, they are placed on the auxiliary instead of on the verb and agree with the object as well as the subject.