Vowels

Wappo has five vowel qualities, but the literature is inconsistent as to whether a length distinction exists. In his Wappo lexicon, Sawyer transcribes long vowels, but Thompson et al., who worked with the same speaker, report that they did not hear any long vowels.^[4][8]

According to Radin, the following diphthongs occur in Wappo: /ao/, /ai/, /ɛo/, /ɛi/, /ɛu/, /ei/, /ɔi/, /iɛ/, and /ui/.^[9]

Consonants

The transcription style (bolded symbols below) is based on Sawyer's work with Somersal, with further interpretation by Thompson, Park and Li. Thompson et al. propose that Wappo has three types of stops: plain, aspirated and glottalized. Stops plus /h/ are therefore treated as single aspirated stops.^[4] Sawyer notes that /f/, /d/, /g/, /r/ and /rʼ/ are used for Spanish borrowings.^[8]

The above table omits ⟨ch⟩ /cʰ/ [tsʰ] and ⟨čh⟩ /čʰ/ [tʃʰ].

Stress and tone

Wappo word stress is predictable, in that the first syllable of the word stem is stressed. In the examples below, the accent marks stress.

• méhwa "wild grape vine"
• kálkuʔ "greyhound"

Wappo does not make distinctions in tone.

Phonological processes

• Glottal stops are inserted word-initially in words that would otherwise begin with a vowel.
• If a word stem ends in a vowel and a suffix immediately following the stem begins with a vowel, one of those vowels is elided. In most cases, the vowel at the beginning of the suffix is deleted. For example, čoči-iʔ, which is the root "weave" plus the durative suffix, has the surface representation of čoči?.^[4]

Nouns

Nouns can be divided into human and non-human classes, which is relevant for pluralization. Human nouns are consistently inflected for plurality, but non-human nouns do not have to be inflected for plurality, even when their reference is in fact plural. For example, onoʔšiʔ-te "Indians" has the plural suffix -te, but mansanaʔi "apples" lacks the suffix.^[4]

Verbs

Wappo also has rich inflectional and derivational morphology in its verb phrases. There are five categories of tense or aspect: habitual/progressive, stative, past, inchoative and future. Each verb root takes at least two forms to which suffixes are added. The form used depends on the tense. The forms themselves are determined by the verb's semantic class, which is basically determined by the habitual/progressive suffix used. Specific suffixes result in changes to the verb stem, for example, -lik- is added to the root of verbs occurring with the rare imperative suffix -laʔ. This occurs in the imperative for "sleep", in which the stem is changed from hinto- to hintolik-. Epenthesis also occurs in certain situations, depending on the form of the root and the suffix added.^[4]

Thompson et al. provide the following examples of tense/aspect categories. The relevant forms are bolded, and all of the forms follow Sawyer's transcription style.

Negatives are marked by the suffix lahkhiʔ.

Prefixes are also added to verb phrases. There are speaker-oriented directional prefixes which are grouped into two classes, depending on whether the motion of the verb is directed at or away from the speaker. In narrative contexts, the direction may refer to a character. For example, two directional prefixes are ma- "away from speaker" and te- "toward speaker". Non-speaker-oriented directional prefixes include ho-, meaning "around" and pi-, meaning "accidentally". Wappo also includes pre-verbal desiderative and optative mood particles. The desiderative particle, k'ah, is used to indicate that the speaker wishes something were true. The optative particle, keye, is translated as "could", "can", or "should".

Word order

Wappo has a predicate-final word order.

Patient-initial structures are acceptable, albeit less common.

Wappo allows for more freedom in word order in complement clauses, especially when they have first person subjects. All three sentences below are acceptable translations of "I know that the man caught a fish".

In noun phrases, demonstrative and genitive modifiers precede the noun, while numerals and adjectives follow the noun.

In verb phrases, oblique arguments and adverbs come before the verb.

Case system

Wappo has a rich case system which uses suffixes to mark cases. In the examples below, the words relevant to the case being discussed are in boldface.

The accusative case is unmarked. Patients, arguments of transitive verbs that are patient-like, all subjects in dependent clauses and single arguments in copulas take the accusative case.

The nominative case is marked with the suffix -i. Words functioning as initiators, agents, experiencers of transitive verbs and the single argument of an intransitive verb take the nominative case. If the noun stem to which this suffix is added happens to ends with a vowel, the stem-final vowel is dropped or changed. Otherwise, adding the nominative suffix does not change the stem. The examples below illustrate the contrast.

• pol'eʔ "boy" → pol'eʔi "boys"
• k'ešu "deer (singular)" → k'eši "deer (plural)"

The dative case, which is used to indicate the recipient or direction, is marked with -thu.

The benefactive case is marked with -ma. It is used to mark whom the action benefits.

The instrumental case, used with intensive reflexives and instruments, is marked with -thiʔ.

The comitative case is marked with -k'a and is used to indicate accompaniment.

The genitive case is marked with -meʔ. It can only be used in constructions with alienable possession. (Inalienable possession is expressed through the juxtaposition of the two relevant nouns.)

Wappo also has a locative case, which is marked with suffixes such as -pi "away from" and -cawoh "on top of".

Yes–no questions

To mark yes–no questions, a question particle, /hVʔ/, is added after the verb. It does not have to directly follow the verb. The particle's vowel harmonizes with the vowel that precedes it. In all of the examples blow, the question word is glossed as "Q" and is also in boldface.

The particle is usually at the end of the sentence, but as the example below demonstrates, it is not always sentence-final. Its location depends on the composition of the verb phrase.

Question-word questions

Question words are usually located clause-initially.

Question words can also get case inflection, except in cases of inalienable possession, where no suffix is added.

Question words can also be used as indefinite pronouns.