Nepali is the national language of Nepal. Besides being spoken as a mother tongue by more than 48% of the population of Nepal, it is also spoken in Bhutan and India. The language is recognized in the Nepali constitution as an official language of Nepal.
The variety presented here is standard Nepali as spoken in Nepal. There are three major dialects: eastern, central, and western. Though many dialects can be distinguished in Nepal and other South Asian countries, there is reported to be little variation in phonology from one to another.
Nepali has 11 phonologically distinctive vowels, including 6 oral vowels and 5 nasal vowels (indicated in the IPA with tildes ~). In addition, due to a process of h-deletion, there are words in which some speakers produce long vowels, such as ? ('mountain') which is phonetically [pa:?] can be analyzed phonemically as /pa?/.
As the above list shows, there are five nasal vowels. The high mid back vowel /o/ does not have a nasal counterpart at the phonological level; although the vowel [õ] does exist phonetically in the language, it is often in free variation with its oral counterpart, as in [hot?so] ~ [hõt?so] 'short', [b?e?a:] ~ [ba:] 'sheep'. Nasal vowels are not frequent in the Nepali lexicon, compared to a language such as French in which the number of nasal vowels is large. They occur mostly in verbs.
According to Bandhu et al. (1971), the evidence for the distinctiveness of vowel nasalization is not nearly as strong as that for the distinctiveness of the six oral vowels. They state that minimal pairs are easily obtainable only for the vowel /a/. Examples are shown below:
Other minimal pairs include /na/ ('name') vs. /nau?/ ('barber') and /?a/ ('village') vs. /?au?/ ('sing' 2nd p. sg. imperative). At the phonetic level, oral vowels can be nasalized when following a nasal consonant.
Pokharel (1989:37-38) followed two diphthongs first elaborated by Shivaraja Acharya in in 1974.
The following rules can be followed to figure out whether or not Nepali words retain the final schwa.
1) Schwa is retained if the final syllable is a conjunct consonant. ? (anta, 'end'), ? (sambandha, 'relation'), ? (?reha, 'greatest'/a last name).
Exceptions: conjuncts such as in ? (mañc, 'stage') ? (gañj, 'city') and occasionally the last name ? (panta/pant).
2) For any verb form the final schwa is always retained unless the schwa-cancelling halanta is present. (huncha, 'it happens'), (bhaera, 'in happening so; therefore'), (gaecha, 'he apparently went'), but (chan, 'they are'), ? (gain, 'she went').
Meanings may change with the wrong orthography: (gaina, 'she didn't go') vs ? (gain, 'she went').
3) Adverbs, onomatopoeia and postpositions usually maintain the schwa and if they don't, halanta is acquired: (aba 'now'), (tira, 'towards'), (?ja, 'today') ? (simsim 'drizzle') vs (jhan, 'more').
4) Few exceptional nouns retain the schwa such as: (dukha, 'suffering'), (sukha, 'pleasure').
Note: Schwas are often retained in music and poetry to facilitate singing and recitation.
Spoken Nepali has 30 consonants in its native system though some have tried to limit the number to 27.
The glides [j] and [w] are nonsyllabic variants of /i/ and /u/, respectively. The combination of the labio-velar approximant /w/ and /e, i, o, ?i?, r, w, j/ is constrained in Nepali, thus the orthographic ??? is always pronounced as a bilabial stop /b/ in such cases, but only sometimes otherwise. All consonants except /j, w, ?/ have geminates between vowels. Apart from forming lexically distinctive words, as in /ts?p?l/ ('unstable') and /ts?p:?l/ ('slipper'), gemination also forms the intensive degree of adjectives, as in /mi:o/ ('very delicious'), compare /mio/ ('delicious').
The murmured stops may lose their breathy-voice between vowels and word-finally. Non-geminate aspirated and murmured stops may also become fricatives, with /p?/ as [?], /b?/ as [?], /k?/ as [x], and // as [?]. Examples of this are /s?p?a/ 'clean' becoming [sa] and /a?i/ 'before' becoming [a?i]).
Typically, sounds transcribed with the retroflex symbols ⟨?, , ?, , ?, ?, ⟩ are not purely retroflex [?, , ?, , ?, ?, ] but apical postalveolar [t?, t, d?, d, , n?, ]. Some speakers may use purely retroflex sounds after /u/ and /a/, but other speakers use the apical articulation in all positions.
Mostly words from Sanskrit have consonants that are not very common in inventory of the spoken language, occurring in borrowed words where they are prescriptively pronounced as described in Sanskrit grammars. The retroflex nasal /?/ occurs in the speech of some speakers, in words such as /ba?/ ('arrow'). It is flapped  in spelling pronunciations of some loanwords in Sanskrit. A posterior sibilant [?] occurs in such words as /nare?/ ? ('king'). The language does not have any minimal pairs opposing /s/ and /?/, and speakers sometimes use these sounds interchangeably.
Nepali syllable structure consists of an optional syllable onset, consisting up to three consonants; an obligatory syllable nucleus, consisting of a vowel; and an optional syllable coda, consisting of one consonant. The following restrictions apply:
Additional consonant(C5) in coda occurs in loanwords and in handful of native words such as /nd?z/ (?) and /m?nt?s/ (?).