Relative articulation

In phonetics and phonology, relative articulation is description of the manner and place of articulation of a speech sound relative to some reference point. Typically, the comparison is made with a default, unmarked articulation of the same phoneme in a neutral sound environment. For example, the English velar consonant /k/ is fronted before the vowel /iː/ (as in keep) compared to articulation of /k/ before other vowels (as in cool). This fronting is called palatalization.

The relative position of a sound may be described as advanced (fronted), retracted (backed), raised, lowered, centralized, or mid-centralized. The latter two terms are only used with vowels, and are marked in the International Phonetic Alphabet with diacritics over the vowel letter. The others are used with both consonants and vowels, and are marked with iconic diacritics under the letter. Another dimension of relative articulation that has IPA diacritics is the degree of roundedness, more rounded and less rounded.

Advanced and retracted

Advanced, retracted
◌̟
◌̠

See also: Fronting (phonetics)

A fronted or advanced sound is one that is pronounced farther to the front of the vocal tract than some reference point. The diacritic for this in the IPA is the subscript plus, U+031F ̟ COMBINING PLUS SIGN BELOW (HTML ̟). Conversely, a retracted or backed sound is one that is pronounced farther to the back of the vocal tract, and its IPA diacritic is the subscript minus U+0320 ̠ COMBINING MINUS SIGN BELOW (HTML ̠). Both consonants and vowels may be fronted or backed.

In English, the back vowel /u/ is farther forward than what is normally indicated by the IPA letter ‹u›. This fronting may be shown explicitly, especially within a narrow transcription: [u̟]. Whether this is as far front as the central vowel [ʉ], or somewhere between [u] and [ʉ], may need to be clarified verbally.

In General American English, the /t/ in the word eighth is farther front than normal, due to assimilation with the interdental consonant /θ/, and may be transcribed as [eɪt̟θ].

The difference between a fronted and non-fronted consonant can be heard in the English words key [k̟ʰi] and coo [kʰu], where the /k/ in key is fronted under the influence of the front vowel /i/.

In verbal description, the prefix pre- may be used to indicated fronting, especially in the terms prepalatal and prevelar. Otherwise phrases like "fronted u" may be used.

In English, the plosive in the affricate /tʃ/, as in the word church, is farther back than an alveolar /t/ due to assimilation with the postalveolar fricative /ʃ/. In narrow transcription, /tʃ/ may be transcribed [t̠ʃʰ].

Languages may have phonemes that are farther back than the nearest IPA symbol. For example, Polish sz is a postalveolar sibilant. While this is often transcribed as [ʃ], it is not domed (partially palatalized) the way a prototypical [ʃ] is. A more precise transcription therefore is [s̠]. Similarly, the velar consonants in Kwakiutl are actually postvelar; that is, pronounced farther back than a prototypical velar, between velar [k] and uvular [q], and is thus transcribed [k̠].

Officially, the IPA symbol [a] stands for a front vowel. However, in most languages where it is used, /a/ actually stands for a central vowel. If precision is desired, this may also be indicated with the minus sign ([a̠]), or possibly with the centralized diacritic ([ä]); yet another possible notation is [ɐ] with the lowered diacritic ([ɐ̞]).

Either the prefix post- may be used to indicated retraction, as above, or phrases like "retracted i" may be used.

Raised and lowered

Raised and lowered
◌̝
◌̞

See also: Raising (phonetics)

A raised sound is articulated with the tongue or lip raised higher than some reference point. In the IPA this is indicated with the uptack diacritic U+031D ̝ COMBINING UP TACK BELOW (HTML ̝).

A lowered sound is articulated with the tongue or lip lowered (the mouth more open) than some reference point. In the IPA this is indicated with the downtack diacritic U+031E ̞ COMBINING DOWN TACK BELOW (HTML ̞). Both consonants and vowels may be marked as raised or lowered.

When there is no room for the tack under a letter, it may be written after, using: U+02D4 ˔ MODIFIER LETTER UP TACK as in [ɭ˔], or U+02D5 ˕ MODIFIER LETTER DOWN TACK as in [ɣ˕].

Raised and lowered vowels

In the case of a vowel, raising means that the vowel is closer, toward the top of the vowel chart. For example, [e̝] represents a vowel somewhere between cardinal [e] and [i], or may even be [i]. Lowering, on the other hand, means that the vowel is more open, toward the bottom of the chart. For example, [e̞] represents a vowel somewhere between cardinal [e] and [ɛ], or may even be [ɛ].

In other non-IPA transcription systems, raised vowels are indicated with the iconic upward-pointing arrowhead U+02F0 ˰ MODIFIER LETTER LOW UP ARROWHEAD (HTML ˰) while lowered vowels have the downward arrowhead U+02EF ˯ MODIFIER LETTER LOW DOWN ARROWHEAD (HTML ˯). Thus, IPA [e̝] is equivalent to [e˰], IPA [e̞] is equivalent to [e˯].

Raised and lowered consonants

With consonants, raising and lowering changes the manner of articulation to something with more or less stricture. For example, raised approximants and trills are fricatives, whereas lowered fricatives are approximants. The ambiguous symbols for rear approximant/fricatives may be specified as fricatives with the raising diacritic, [ʁ̝, ʕ̝, ʢ̝], or as approximants with the lowering diacritic, [ʁ̞, ʕ̞, ʢ̞]. In Spanish, the lenited allophones of the voiced stops are generally transcribed as fricatives even though they are approximants, or intermediate between fricative and approximant. This may be partially due to the fact there is only a dedicated IPA symbol for one of them, the velar approximant. More precise transcription will use the fricative symbols with the lowering diacritic, [β̞, ð̞, ɣ˕] (the last symbol may be rendered as [ɣ̞], but that may not display properly in some browsers). Czech, on the other hand, requires the opposite: Its fricated trill, which is a separate phoneme, may be transcribed as a raised trill, [r̝]. Similarly, the non-sibilant coronal fricative is written [ɹ̝], and the voiceless velar lateral fricative as [ʟ̝̊]. (A dedicated letter for this sound, ⟨⟩, is not part of the IPA.)

From most open (least stricture) to most close (most stricture), there are several independent relationships among speech sounds. Open vowel → mid vowel → close vowel → approximant → fricative → plosive is one; flap → stop is another; and trill → trilled fricative yet another. The IPA chart has been organized so that the raising diacritic moves the value of a letter through these series toward the top of the chart, and the lowering diacritic toward the bottom of the chart, but this only works for some of the consonants. While it would be convenient if all consonants could be so ordered, consonants are too diverse for a single dimension to capture their relationships. In addition, many of the points along the series may be nasalized or lateralized as well, and these parameters are independent of stricture.

Examples of stricture series

	Oral	Nasal	Flap	Trill	Lateral
Stop	ɟ	ɲ	d		t͡ɬ
Fricative	ʝ	ʝ̃		r̝	ɬ
Approximant / Vibrant	j	ȷ̃	ɾ	r	l
Close vowel	i	ĩ	(N/A)
Near-close vowel	e̝	ẽ̝
Close-mid vowel	e	ẽ
Mid vowel	e̞	ẽ̞
Open-mid vowel	ɛ	ɛ̃
Near-open vowel	æ	æ̃
Open vowel	a	ã

Centralized vowels

Centralized
◌̈

For non-lateral consonants, see Central consonant.

A centralized vowel is a vowel that is more central than some point of reference, or that has undergone a shift in this direction. The diacritic for this in the International Phonetic Alphabet is the dieresis, U+0308 ̈ COMBINING DIAERESIS (HTML ̈).

For example, to transcribe rounded and unrounded near-close central vowels, the symbols [ɪ̈, ʊ̈] may be used.

In other (non-IPA) transcription systems, ‹ɪ, ʊ› (or ᵻ, ᵿ) will be seen instead of [ɪ̈, ʊ̈] (by analogy with [ɨ, ʉ]). Before the letters [ɘ, ɵ, ɜ, ɞ] were added to the IPA in 1993, the symbols [ë, ö, ɛ̈, ɔ̈] were used for these near-schwa values. [ë, ö, ɛ̈, ɔ̈] would now be assumed to represent articulations intermediate between [e, o, ɛ, ɔ] and [ɘ, ɵ, ɜ, ɞ]. Similarly, [ï, ÿ, ü, ɯ̈] would be intermediate between [i, y, u, ɯ] and [ɨ, ʉ].

In the majority of languages described as having an [a], the vowel is actually central and would be better transcribed as [ä]. However, this symbol is not commonly used mainly because of the common practice of avoiding using diacritics wherever possible.

Instead of the diacritic for centralization, the advanced or retracted diacritics may be used (an equivalent transcription of [ä] is retracted [a̠]), but the concept of centralization is convenient in cases where front and back vowels move toward each other, rather than all advancing or retracting in the same direction.

Mid-centralized vowel

Mid-centralized
◌̽

A mid-centralized vowel is a vowel closer to the midpoint of the vowel space than some point of reference. That is, it is closer to the mid-central vowel schwa [ə]; it is not just centralized, but also raised or lowered. The diacritic used to mark this in the International Phonetic Alphabet is the over-cross, U+033D ̽ COMBINING X ABOVE (HTML ̽).

In most languages, vowels become mid-centralized when spoken quickly, and in some, such as English and Russian, many vowels are also mid-centralized when unstressed. This is a general characteristic of vowel reduction.

Even when fully articulated, the vowels of a language may be on the schwa side of a cardinal IPA vowel. One example of this is Lisbon Portuguese, where unstressed e is a near-close near-back unrounded vowel. That is, it lies between the close back unrounded vowel [ɯ] and schwa, where [ʊ] sits in the vowel chart, but unlike [ʊ], not rounded. It may be written [ɯ̽], as in pegar [pɯ̽ˈɣaɾ] "to hold".

More and less rounded

More or less rounded
◌̹
◌̜

There are also diacritics, respectively U+0339 ̹ COMBINING RIGHT HALF RING BELOW and U+031C ̜ COMBINING LEFT HALF RING BELOW, to indicate greater or lesser degrees of rounding. For example, the English near-close near-back vowel often has very little rounding, and may be transcribed [ʊ̜]. In Assamese, on the other hand, the open back rounded vowel is much more rounded than is typical for a low vowel, and may be transcribed [ɒ̹].

These diacritics are sometimes also used with consonants to indicate degrees of labialization. For example, in the Athabaskan language Hupa, voiceless velar fricatives distinguish three degrees of labialization, transcribed either [x x̹ xʷ] or [x x̜ʷ xʷ].

The Extensions to the IPA have two additional symbols for degrees of rounding: spread, as in [ə͍], and open-rounded ⟨ꟹ⟩ (^œ), as in English [ʃ^œ] and [ʒ^œ].

Sound changes

Some sound changes involve change in place of articulation:

• raising (phonology)
• fronting (phonology)
• i-mutation (vowel raising and fronting before [i] or [j])
• imāla (/a/ raising in Arabic)
• iotacism (vowel raising in Greek)