Consonants

In addition, the phonemes /b/, /c/, /ɡ/, /ŋ/, and /h/ occur only in loans, mostly from Indonesian, Tetum, and the local variety of Malay.

Vowels

These vowels can also occur long; the phonemic status of long vowels hangs on the interpretation of Leti's pervasive metathetic processes.

The mid vowels /e, o, ɛ, ɔ/ are restricted to the penult of lexical morphemes, which is stressed. The majority of these morphemes provide no evidence for the height contrast — /ɛ, ɔ/ are found before an ultimate /a/ and /e, o/ in other positions — and diachronically there was no contrast. However, the contrast is set up synchronically on account of certain exceptions (/ea/ 'he, she', /msena/ 'refuse', /dena/ 'stay'), and the fact that when suffixed the conditioning vowel can disappear:

/kɛrna/ 'dry' → /ŋkɛrnulu/ 'it dries first'

/kernu/ 'descend' → /ŋkernulu/ 'he descends first'

Phonological processes

Metathesis and apocope, together binding processes, are pervasive in Leti as a feature of combinations of morphemes. The preferred "flow of speech" in Leti seems to involve chains of CCV units.

The free form of any Leti morpheme always features a final vowel, so those whose bound forms end in consonants feature two allomorphs which are related by CV metathesis. Thus 'skin, fly (n.), fish, bird' have bound forms /ulit, llaran, iina, maanu/ (the latter two with long vowels) but free forms /ulti, llarna, ian, maun/.

When a morpheme whose bound form ends in a vowel is prefixed to another component, that final vowel may apocopate or metathesise into the following component. CV metathesis happens when the metathesising vowel is high and is followed by at most one consonant and a non-high vowel. The metathesised vowel is realised as a glide, [j w] written as ï ü. Thus sivi + ternu 'chicken + egg' becomes sivtïernu 'chicken egg', au + laa 1st sing. pronoun + 'go' becomes alüaa 'I go'. In other contexts apocope happens, unless this would leave an illicit three-consonant cluster. So sivi + ruri 'chicken + bone' becomes sivruri 'chicken bone', kusa + nama 'cat + tongue' becomes kusnama 'cat's tongue'.

A similar metathesis is found with the nominaliser, historically an infix -in-, but now taking the form -nï- among many other allomorphs (detailed more below): thus sora 'sew' derives snïora 'needle'.

Morphology

Human nouns pluralise with the third person plural pronominal clitic -ra, which must follow another suffixed element: püata 'woman', püat=e 'the woman', püat=e=ra 'the women'. Nonhuman nouns pluralise by repetition: kuda 'horse', kuda kuda 'horses'.

Leti has four possessive suffixes, which undergo binding.

The vowel V in the first person plural and third person suffix copies the last vowel of its base.

Nouns can be zero-derived to verbs: e.g. rita 'roof' → na-rita 'he roofs' or 'it has a roof'.

Nominal compounding is highly productive as a derivational process. For example rai + lavna 'king' + 'big' → ralïavna 'emperor', pipi + ïadmu 'goat' + 'shed' → pipïadmu 'goat shed', vutu + müani 'ribbon' + 'man' → vutumüani 'man's ribbon', vika + papa 'buttocks' + 'cucumber' → vikpapa 'cockroach', kapla + nèma reduplicated 'ship' + 'fly' → kapalnèmnèma 'airplane'.

Verbs fall into two classes according to whether their subject prefixes exhibit binding or not: those of Class I do not, those of Class II do. By default verbs are in Class II. Certain verbs are lexically in Class I (like nòa 'advise'), together with all verbs with complex onsets (ssòrna 'cough') and denominal or causativised verbs (veli 'buy', from the noun veli 'price'). The subject prefixes are as follows.

Verbs with first person singular inflection necessarily take the pronoun a= 'I' as a proclitic.

Some causatives are marked only by class change: pali means 'float' in class II and 'make float' in class I.

The nominalising affix productively derives nouns from verbs. It takes various forms, most of which are infixes, depending on the phonological shape and the class of its base.

Reduplication, which usually copies a root-initial CV or CVCV sequence with binding, has a variety of functions, among them adjectivisation of nouns (üau 'idiot' → üa-üau 'idiotic') and verbs (mèra 'redden' → mèr-mèra), derivation of nouns, especially instruments (sòra 'sew' → sòr-sòra 'needle'), marking atelicity, and relativising on an object (n-vèèta 'he pulls' → (n-)vèvèèta 'which he pulls').

Lexical parallelism

Many of Leti's lexical items are organised into lexical pairs, which are always deployed as fixed combinations in a fixed order. A few pairs involve adjectives or numerals, but the vast majority consist of nouns (e.g. püata // müani 'woman // man', üèra // vatu 'water // stone') or verbs (e.g. kili // toli 'look // see', keri // kòi 'scratch / scrape').

Some words are confined to lexical pairs, such as tirka in tirka // llena 'lightning', or both dupla and mavla in dupla // mavla 'witchcraft'; these pairs are restricted to lirmarna. In lirmarna the function of lexical pairs is to highlight particular elements of a sentence, or simply to mark formality. When used in ordinary speech, the meanings of lexical pairs can relate in various ways to those of their components:

leli // masa 'ivory // gold', meaning 'treasure'

lòi // spou 'proa // sailing boat', meaning 'traditional fleet'

nusa // rai 'island // mainland', meaning 'archipelago'

ili // vatu 'hill // stone', meaning 'fort'

püata // müani 'woman // man', meaning either 'married couple' or 'gender'

Or they can simply have the sense of a conjunction, e.g. asu // vavi 'dog // pig' = 'the dog and the pig'; these are the only sort of conjoined phrases that do not require the conjunction na.