The close and mid vowels are typically peripheral, but they can at times be somewhat centralized.
/i, iː, u, uː/ are typically near-close [i̞, i̞ː, u̞, u̞ː], but sometimes they can be close [i, iː, u, uː] instead.
/ɛ, ɛː, ɔ, ɔː/ are typically mid [ɛ̝, ɛ̝ː, ɔ̝, ɔ̝ː]. /ɛ, ɛː/ are slightly higher than /ɔ, ɔː/ - this can be transcribed in narrow transcription as [e̞, e̞ː] vs. [ɔ̝, ɔ̝ː]. At times, /ɛ, ɛː/ can be as close as close-mid [e, eː] and /ɔ, ɔː/ as open as open-mid [ɔ, ɔː].
Speakers often fail at attempts to pronounce /æ/, pronouncing a vowel that is phonetically too close to either /ɛ/ or /a/.
/a, aː/ are typically open central [ä, äː], but at times they can be somewhat fronted [a̠, a̠ː], retracted [ɑ̟, ɑ̟ː] or raised [ɐ, ɐː].
Under Hungarian influence, some speakers realize /ɛː, ɔː/ as close-mid [eː, oː] and /a/ as open back rounded [ɒ]. The close-mid realizations of /ɛː, ɔː/ occur also in southern dialects spoken near the river Ipeľ.
Vowel length is not phonemic in Eastern dialects, which have only five vowel phonemes (/i, u, ɛ, ɔ, a/, some speakers also have /æ/).
In Western dialects, vowels that are short due to the rhythmical rule are often realized as long, and thus violating the rule.
/y, yː, œ, œː, ɔː/ occur only in loanwords. Just as other mid vowels, /œ, œː/ are phonetically true-mid [œ̝, œ̝ː]. Among these vowels, only /ɔː/ is consistently realized in the correct manner, whereas the occurrence of the front rounded vowels /y, yː, œ, œː/ has been reported only by Kráľ (1988), who states that the front rounded vowels appear only in the high register and medium register. However, in the medium register, /y, yː/ and /œ, œː/ are often either too back, which results in realizations that are phonetically too close to, respectively, /u, uː/ and /ɔ, ɔː/, or too weakly rounded, yielding vowels that are phonetically too close to, respectively, /i, iː/ and /ɛ, ɛː/.
/uː, ɛː/ do not occur after soft consonants, where they are replaced by the corresponding diphthongs /ɪ̯u, ɪ̯ɛ/. The same is generally true for /aː/ (/ɪ̯a/ after soft consonants), but the sequence /jaː/ may occur in some cases.
Long /ɛː/ occurs only in loanwords, one native word (dcéra) and in adjective endings.
/æ/ can only be short, and occurs only after /m, p, b, v/. There is not a full agreement about its status in the standard language:
Kráľ (1988) states that the correct pronunciation of /æ/ is an important part of the high register, but in medium and low registers, /æ/ merges with /ɛ/, or, in some cases, with /a/.
Short (2002) states that only about 5% of speakers have /æ/ as a distinct phoneme, and that even when it is used in formal contexts, it is most often a dialect feature.
All of the diphthongs are rising, i.e. their second elements have more prominence.
The phonetic quality of Slovak diphthongs is as follows:
/ɪ̯ɛ/ is typically a glide from /i/ to /ɛ/ ([ȋ̞ɛ̝]).
/ɪ̯a/ is typically a glide from the position below /i/ to /æ/ ([ȇ̝æ̠]).
/ɪ̯u/ is typically a glide from /i/ to the position more front than /u/ ([ȋ̞ʊ]).
/ʊ̯ɔ/ is typically a glide from /u/ to the position above /ɔ/ ([ȗ̞o̞]).
There are many more phonetic diphthongs, such as [aʊ̯] in Miroslav[ˈmirɔslaʊ̯] and [ɔʊ̯] in Prešov[ˈprɛʃɔʊ̯]. Phonemically, these are interpreted as sequences of /v/ preceded by a vowel. This [ʊ̯] is phonetically [ȗ̞] and it is very similar to the first element of /ʊ̯ɔ/.
Pavlík (2004) describes an additional realization, namely a weakly palatalized apical alveolar approximant [l̺ʲ]. According to this scholar, the palatal realization [ʎ] is actually alveolo-palatal [ʎ̟].
The /ʎ–l/ contrast is neutralized before front vowels, where only /l/ occurs. This neutralization is taken further in western dialects, in which /ʎ/ merges with /l/ in all environments.
/j/ is an approximant, either palatal or alveolo-palatal. Between close front vowels, it can be realized as a fricative [ʝ], whereas between open central vowels, it can be a quite lax approximant [j˕].
Some additional notes includes the following (transcriptions in IPA unless otherwise stated):
/r, l/ can be syllabic: /r̩, l̩/. When they are long (indicated in the spelling with the acute accent: ŕ and ĺ), they are always syllabic, e.g. vlk (wolf), prst (finger), štvrť (quarter), krk (neck), bisyllabic vĺča—vĺ-ča (wolfling), vŕba—vŕ-ba (willow-tree), etc.
/m/ has the allophone [ɱ] in front of the labiodental fricatives /f/ and /v/.
/n/ in front of (post)alveolar fricatives has a postalveolar allophone [n̠].
/n/ can be [ŋ] in front of the velar plosives /k/ and /ɡ/.
In the standard language, the stress is always on the first syllable of a word (or on the preceding preposition, see below). This is not the case in certain dialects. Eastern dialects have penultimate stress (as in Polish), which at times makes them difficult to understand for speakers of standard Slovak. Some of the north-central dialects have a weak stress on the first syllable, which becomes stronger and moves to the penultimate in certain cases. Monosyllabic conjunctions, monosyllabic short personal pronouns and auxiliary verb forms of the verb byť (to be) are usually unstressed.
Prepositions form a single prosodic unit with the following word, unless the word is long (four syllables or more) or the preposition stands at the beginning of a sentence.
Slovak linguists do not usually use IPA for phonetic transcription of their own language or others, but have their own system based on the Slovak alphabet. Many English language textbooks make use of this alternative transcription system.
In the following table, pronunciation of each grapheme is given in this system as well as in the IPA.
Rubach, Jerzy (1995), "Representations and the organization of rules in Slavic phonology", in Goldsmith, John A. (ed.), The handbook of phonological theory (1st ed.), Oxford: Blackwell, pp. 848–866, ISBN978-0631180623
Sabol, Ján (1961), "O výslovnosti spoluhlásky v", Slovenská reč, 6: 342–348