The International Phonetic Alphabet (IPA) consists of letters and diacritics. The majority of  Lithuanian sounds are represented by regular letters used in the Lithuanian writing system (e.g. the consonants [t, d, k, m]), but some sounds are represented by some special characters (e.g. [ʃ] for š, [ʒ] for ž, [ʋ] for v). Diacritics denote different sound features; for example, the symbol ⟨ː⟩ marks long vowels (e.g. [ɑː]); the symbol ⟨ˑ⟩ indicates half-long vowels (e.g. [ɑˑ]); consonant softness is marked by ⟨ʲ⟩ (e.g. [lʲ]); and vowel fronting is marked by ⟨ ̟⟩ (e.g. [u̟ː]). A summary of all the symbols is provided in Table 1. The table does not include the gliding vowels ie, uo, and are transcribed as [iɛ] and [uɔ] respectively. Unlike other vowels, their duration is not marked by additional diacritics, e.g. pi̇́enas [1ˈpʲiɛnɐs] (‘milk’, singular nominative), šiẽnas [2ˈʃʲiɛnɐs] (‘hay’, singular nominative), púodas [1ˈpuɔdɐs] (‘pot’, singular nominative), puõtą [2ˈpuɔtɑː] (‘feast’, singular nominative).

Table 1. Lithuanian letters and sounds

Letter, digraph  International Phonetic Alphabet
 A a  ɑː ɐ
 Ą ą  ɑː
 B b  b bʲ
 C c  ʦ ʦʲ
 Ch ch  x xʲ
 Č č  ʧ ʧʲ
 D d  d dʲ
 Dz dz  ʣ ʣʲ
 Dž dž  ʤ ʤʲ
 E e  æː ɛ
 Ę ę  æː
 Ė ė  eː
 F f  f fʲ
 G g  ɡ ɡʲ
 H h  ɣ ɣʲ
 I i  ɪ
 Į į  iː
 Y y  iː
 J j  j
 K k  k kʲ
 L l  l lʲ
 M m  m mʲ
 N n  n nʲ (before k, g, h, ch – ŋ ŋʲ)
 O o  oː ɔ
 P p  p pʲ
 R r  r rʲ
 S s  s sʲ
 Š š  ʃ ʃʲ
 T t  t tʲ
 U u  ʊ
 Ų ų  uː
 Ū ū  uː
 V v  ʋ ʋʲ
 Z z  z zʲ
 Ž ž  ʒ ʒʲ

 

Diacritics are used not only to mark sound properties but also some other phonetic phenomena.

At the juncture of two vowels belonging to different syllables (that is, vowels not forming a diphthong), the hiatus diacritic ⟨.⟩ is used, e.g. preangis [1ˈpʲrʲɪɛ.ɐŋʲgʲɪs] (‘entryway’, singular nominative).

In the IPA, stressed short syllables are marked by ⟨ˈ⟩, syllables with an acute are marked by ⟨¹⟩, those with a circumflex are marked by ⟨²⟩, and a secondary stress is represented by ⟨ˌ⟩, e.g. kalbà [kɐlˈbɐ] (‘language’, singular nominative), bártis [¹ˈbɑˑrʲtʲɪs] (‘quarrel’, infinitive), banis [²ˈbɐrʲˑnʲɪs] (‘quarrel’, singular nominative), keturiasdešitas [ˌkʲɛtʊrʲɛzʲdʲɛ²ˈʃʲɪmˑtɐs] (‘forty’). The secondary stress is marked only in dictionaries. In transcription, accent-specific diacritics are written before the stressed vowel.

In Lithuanian linguistics, the prevailing view is that a word usually has only one stress, but some compounds are pronounced with a fairly well-heard secondary accent, e.g. kẽturiasdešimt [²ˈkʲæːtʊrʲɛzʲˌdʲɛʃʲɪmt] (‘forty’), antieuropiẽtiškas, -a – [ɐnʲˌtʲɪ.ɛʊrɔ²ˈpʲiɛtʲɪʃkɐs] (‘anti-European’, singular nominative masculine).

When a monosyllabic (sometimes also polysyllabic) unaccented word (the so-called clitic) appears in combination with an accented word, it is linked to the accented word by the diacritic ⟨‿⟩, e.g. iš nam [ɪʃ‿nɐ2‘muː] (‘out of the house’).

In transcription, the end of an intonation unit is marked by ⟨ǁ⟩, and the end of an internal intonation unit (syntagm) is marked by ⟨ǀ⟩, e.g. Ka nustójo lýti, išėjaũ į kiẽmą. [2ˈkɐɪˑ nʊ1ˈstoːjo̟ː 1ˈlʲiːtʲɪ ǀ ɪʃʲeː2ˈjɛʊˑ iː‿2ˈkʲiɛmɑː ǁ] (‘When it stopped raining, I went out to the yard.’).

In the transcriber, the changes in the contour of the intonation are not indicated, and the boundaries of prosodic units coincide with the boundaries of the sentence; the boundaries of internal units are very preliminary and often correspond to the punctuation marks within the sentence.

In cases of adjacent independent words, the phonetic alignment of consonants, which is common in actual speech (especially in faster speech), is not taken into consideration. When morphemes or a clitic and an independent word are combined, the phonetic alignment of sounds is consistently accounted for.