nly consonant clusters allowed are syllable initial clusters /kw/ or /kʰw/. Any consonant may appear in the onset, but the labialized consonants do not occur before rounded vowels.
Only /p t k ʔ m n ŋ w j/ may appear in the coda. If the vowel in the nucleus is short, it must be followed by a consonant in the coda; /ʔ/ in the coda can be preceded only by a short vowel. Open syllables (i.e. those with no coda consonant) and syllables ending in one of the sonorants /m n ŋ w j/ take one of the six tones, syllables ending in /p t k/ take one of four tones, and syllables ending in /ʔ/ take one of only two tones.
The majority of Lao words are monosyllabic, and are not inflected to reflect declension or verbal tense, making Lao an analytic language. Special particle words serve the purpose of prepositions and verb tenses in lieu of conjugations and declensions. Lao is a subject–verb–object (SVO) language, although the subject is often dropped. In contrast to Thai, Lao uses pronouns more frequently.
The Lao religious script is written in the Tua Tham script, based on Mon scripts and still used in temples in Laos and Isan. The Lao script (Tua Lao), derived locally around the 14th century from the Khmer script of Angkor, is ultimately rooted in the Brahmic script of India. Although similar to one another, the Lao alphabet is more phonetic than the Thai alphabet due to various Lao royal decrees concerning orthographic reforms, resulting in the Lao script having fewer duplicate sounds thus making the Lao script more phonetic, efficient and easy to learn.
Words are spelt according to phonetic principles as opposed to etymological principles. In addition to consonants having tone classes, tone marks facilitate marking tones where they are needed. Romanisation of Lao is inconsistent, but is based on French transcriptive methods.
Lao is traditionally not written with spaces between words, although signs of change are multiplying. Spaces are reserved for ends of clauses or sentences. Periods are not used, and questions can be determined by question words in a sentence. Traditional punctuation marks include ໌, an obsolete mark indicating silenced consonants; ໆ, used to indicate repetition of the preceding word; ຯ, the Lao ellipsis that is also used to indicate omission of words; ฯ, a more or less obsolete symbol indicating shortened form of a phrase (such as royal names); and ฯລฯ, used to indicate et cetera.
In more contemporary writing, punctuation marks are borrowed from French, such as exclamation point !, question mark ?, parentheses (), and «» for quotation marks, although "" is also common. Hyphens (-) and the ellipsis (...) are also commonly found in modern writing.
Indication of tones
Experts disagree on the number and nature of tones in the various dialects of Lao. According to some, most dialects of Lao and Isan have six tones, those of Luang Prabang have five. Tones are determined as follows:
|Tones||Long vowel, or vowel plus voiced consonant||Long vowel plus unvoiced consonant||Short vowel, or short vowel plus unvoiced consonant||Mai ek (ອ່)||Mai tho (ອ້)|
|High consonants||rising||low falling||high||mid||low falling|
|Mid consonants||low rising||low falling||high||mid||high falling|
|Low consonants||high||high falling||mid||mid||high falling|
A silent ຫ (/h/) placed before certain consonants will produce place the other proceeding consonant in the high class. This can occur before the letters ງ /ŋ/, ຍ /ɲ/, ຣ /r/, and ວ /v/ and combined in special ligatures (considered separate letters) such as ຫຼ /l/, ໜ /n/, and ໝ /m/. In addition to ອ່ (low tone) and ອ້ (falling tone), there also exists the rare ອ໊ (high) ອ໋ (rising) tone marks.
- ca. 20M Isan, 3M Laotian
- Lao language at Ethnologue (18th ed., 2015)
- Hammarström, Harald; Forkel, Robert; Haspelmath, Martin; Bank, Sebastian, eds. (2016). "Lao". Glottolog 2.7. Jena: Max Planck Institute for the Science of Human History.
- Hammarström, Harald; Forkel, Robert; Haspelmath, Martin; Bank, Sebastian, eds. (2016). "Northeastern Thai". Glottolog 2.7. Jena: Max Planck Institute for the