The consonant inventory of Luxembourgish is quite similar to that of Standard German.
/m, p, b/ are bilabial, /p͡f/ is bilabial-labiodental, whereas /f, v/ are labiodental./p͡f/ occurs only in loanwords from Standard German. Just as among many native German-speakers, it tends to be simplified to [f] word-initially. For example, Pflicht ('obligation') is pronounced [fliɕt], or in careful speech [p͡fliɕt]./v/ is realized as [w] when it occurs after /k, t͡s, ʃ/, e.g. zwee [t͡sweː] ('two')./p, t, k/ are voiceless fortis [p, t, k]. They are aspirated [pʰ, tʰ, kʰ] in most positions, but not when /s/ or /ʃ/ precedes in the same syllable, or when another plosive or affricate follows.If followed by a vowel, the fortis stops are moved to the onset of the following syllable and voiced to [b, d, ɡ]; see below./b, d, ɡ/ are unaspirated lenis, more often voiceless [b̥˭, d̥˭, ɡ̊˭] than voiced [b˭, d˭, ɡ˭]./d͡z/ as a phoneme appears only in a few words, such as spadséieren /ʃpɑˈd͡zɜɪ̯əʀən/ ('to go for a walk'). /d͡ʒ/ as a phoneme occurs only in loanwords from English.Note that phonetic [d͡z] and [d͡ʒ] occur due to voicing of word-final /t͡s/ and /t͡ʃ/; see below./s/ does not occur word-initially except in French and English loanwords. (In the oldest loans from French it is often replaced with /t͡s/.) /s/ and /z/ only contrast between vowels./ŋ, k, ɡ/ are velar, /ʀ/ is uvular, whereas /j/ is palatal.The normal realization of /ʀ/ is more often a trill [ʀ] than a fricative [ʁ]. The fricative variant is used after short vowels before consonants. If the consonant is voiceless, the fricative is also voiceless, i.e. [χ]. Older speakers use the consonantal variant [ʀ ~ ʁ] also in the word-final position, where younger speakers tend to vocalize the /ʀ/ to a central vowel [ə] or [ɐ]./j/ is frequently realized as [ʒ], e.g. Juni [ˈjuːniː] or [ˈʒuːniː] ('June')./χ, ʁ/ have two types of allophones: alveolo-palatal [ɕ, ʑ] and velar/uvular [χ, ʁ]. The latter occur after back vowels, whereas the former occur in all other positions.The [ʑ] allophone appears only in a few words intervocalically, e.g. Spigel [ˈʃpiʑəl] ('mirror'), héijen [ˈhɜɪ̯ʑən] (inflected form of héich 'high'). Note that an increasing number of speakers do not distinguish between the alveolo-palatal allophones [ɕ, ʑ] and the postalveolar phonemes /ʃ, ʒ/.There is not a complete agreement about the nature of the posterior allophones of /χ, ʁ/; Gilles & Trouvain (2013) describe them as uvular [χ, ʁ], whereas Trouvain & Gilles (2009) describe them as velar [x, ɣ]./l/ is always "clear" [l], never "dark" (velarized) *[ɫ].In external sandhi, syllable-final /n/ is deleted unless followed by [n t d t͡s h], with few exceptions. Furthermore, some unusual consonant clusters may arise post-lexically after cliticisation of the definite article d' (for feminine, neuter and plural forms), e.g. d'Land [dlɑnt] ('the country') or d'Kräiz [tkʀæːɪ̯t͡s] ('the cross'). Due to cluster simplification this article often disappears entirely between consonants.
Phonetically, word-final /b, d, d͡ʒ, ɡ, v, z, ʒ, ʁ ~ ʑ/ are realized exactly the same as /p, t, t͡ʃ, k, f, s, ʃ, χ ~ ɕ/. In most cases, they are realized the same as the main allophones of /p, t, t͡ʃ, k, f, s, ʃ, χ ~ ɕ/ (i.e. voiceless), but when the next word begins with a vowel and is pronounced without a pause, they are realized the same as the main allophones of /b, d, d͡ʒ, ɡ, v, z, ʒ, ʁ ~ ʑ/, i.e. voiced and are resyllabified, that is, moved to the onset of the first syllable of the next word (the same happens with /ts/, which becomes [d͡z], and the non-native affricate /p͡f/, which is also voiced to [b͡v]). For instance, sech eens is pronounced [zəˈʑeːns], although this article transcribes it [zəʑ‿ˈeːns] for simplicity. Similarly, eng interessant Iddi [eŋ intʀæˈsɑnd‿ˈidi] ('an interesting idea').
In Luxembourgish, the letter g has no fewer than nine possible pronunciations, depending both on the origin of a word and the phonetic environment. Natively, it is pronounced [ɡ] initially and [ʁ ~ ʑ] elsewhere, the latter being devoiced to [χ ~ ɕ] at the end of a morpheme. Words from French, English and (in a few cases) German have introduced [ɡ] (devoiced [k]) in other environments, and French orthography's "soft g" indicates [ʒ] (devoiced [ʃ]).
By the now very common mergers of [ʒ] and [ʑ], as well as [ʃ] and [ɕ], this number may be reduced to seven, however. The pronunciation [j] is also (generally) not obligatory but a common allophone of [ʑ] in the environment indicated below.
/i, iː/ are close front unrounded [i, iː].The front rounded vowels /y, yː, øː, œ, œː/ appear only in loanwords from French and Standard German. /œ/ is often merged into /ə/ (particularly in German loanwords).In loanwords from French, nasal /õː, ɛ̃ː, ɑ̃ː/ also occur./u, uː/ are close back rounded [u, uː]./e/ has two allophones:Before velars: close-mid front unrounded [e], which for some speakers may be open-mid [ɛ] – this is especially frequent before /ʀ/.All other positions: mid central vowel, more often slightly rounded [ɵ̞] than unrounded [ə]. Contrary to Standard German, the sequence of /ə/ and a sonorant never results in a syllabic sonorant; however, Standard German spoken in Luxembourg often also lacks syllabic sonorants, so that e.g. tragen is pronounced [ˈtʀaːɡən], rather than [ˈtʀaːɡn̩] or [ˈtʀaːɡŋ̍]./ə/ does not occur word-finally except where a trailing /n/ has been deleted by the Eifeler Regel./eː/ has been variously described as near-close front unrounded [e̝ː] and close-mid front unrounded [eː]. The near-close realization may overlap with /i/.Before /ʀ/ it is realized as open-mid front unrounded [ɛː]. French and German loanwords may also include [ɛː] in other positions./o/ is close-mid back rounded [o]. Especially before /ʀ/, it may be open-mid [ɔ] for some speakers./oː/ has been variously described as near-close back rounded [o̝ː] and close-mid back rounded [oː]. The near-close realization may overlap with /u/./æ/ has been variously described as slightly lowered near-open front unrounded [æ̞] and near-open front unrounded [æ]./aː/ is the long variant of /ɑ/, not /æ/ (which does not have a long counterpart). It has been variously described as slightly retracted open front unrounded [aː] and open front unrounded [aː]. Sometimes it may have the same quality as the short /æ/./ɑ/ has been variously described as near-open back unrounded [ɑ̝] and open near-back unrounded [ɑ̟].The unstressed, non-prevocalic sequence /əʀ/ is realized as a low unrounded vowel, the quality of which has been variously described as near-open near-back vowel [ɐ̠] and near-open central vowel [ɐ].Trouvain & Gilles (2009) transcribe /ə, ɑ̃ː/ as /ë, ãː/.
/iə̯/ begins in the close front unrounded area [i], ends in the mid central unrounded area [ə]./uə̯/ begins in the close back rounded area [u], ends in the mid central unrounded area [ə]./ɜɪ̯/ has two variants:A variant which begins in the mid central unrounded area [ə], ends in the close front unrounded area [i].A variant which begins in the mid near-front unrounded area [e̽], ends in the close front unrounded area [i]. The starting point of this variant has also been described as close-mid front [e]./oɪ̯/ appears only in loanwords from Standard German./əʊ̯/ begins in the mid central unrounded area [ə], ends in the close back rounded area [u]./æːɪ̯/ begins open front unrounded area [a], ends in the close front unrounded area [i]. The starting point has also been described as somewhat higher, i.e. near-open [æ].The first element may be phonetically short in fast speech or in unstressed syllables./æːʊ̯/ begins in the open front unrounded area [a], ends in the close back rounded area [u]. The starting point has also been described as somewhat higher, i.e. near-open [æ].The first element may be phonetically short in fast speech or in unstressed syllables./ɑɪ̯/ begins in the near-open back unrounded area [ɑ̝], ends in the close front unrounded area [i]. The starting point has also been described as somewhat lower, i.e. open [ɑ]./ɑʊ̯/ begins in the near-open back unrounded area [ɑ̝], ends in the close back rounded area [u]. The starting point has also been described as somewhat lower, i.e. open [ɑ].Trouvain & Gilles (2009) transcribe /ɜɪ̯, oɪ̯, æːɪ̯, æːʊ̯/ as /eɪ̯, ɔɪ̯, æˑɪ̯, æˑʊ̯/.
The /æːɪ̯ – ɑɪ̯/ and /æːʊ̯ – ɑʊ̯/ contrasts arose from the former lexical tone contrast; the shorter /ɑɪ̯, ɑʊ̯/ were used in words with Accent 1, whereas the lengthened /æːɪ̯, æːʊ̯/ were used in words with Accent 2.
Additional phonetic diphthongs arise after vocalisation of /ʀ/. These are [iːɐ̯, uːɐ̯, oːɐ̯, ɛːɐ̯]. However, the sequence /aːʀ/ is realized the same as long /aː/, unless a vowel follows within the same word.
