Anyone with a linguistic ear who wanders about the Indo-Iranian Frontier1 cannot fail to notice the variety of "accents" that distinguish the region's numerous linguistic communities. Speakers of these languages employ a small repertoire of articulatory processes that have determined the phonological distinctiveness and evolution of today's languages throughout the Indo-Iranian region. Basic among these processes are Front and Back Tensing of the larynx. Augmenting these are the processes of Backing or Fronting of the root of the tongue, Opening and Prognathizing of the jaw, and Raising of the velum. Throughout their evolution the various linguistic communities of the Frontier have chosen combinations of these processes to express their linguistic "attitude."
The analysis presented here is based on phonological data that I collected on numerous field trips to the region of greatest linguistic diversity, where the Indo-Iranian Frontier transverses the Hindu-Kush Range, from 1967-1992. In this region the westernmost of the Indo-Aryan languages remain surrounded within the southern watershed of the Hindu-Kush by eastward intrusions of Iranian speakers to the north and south. The northern edge of the Frontier runs along the crest of the Hindu-Kush Range from Kâpisâ and Panjshir in the west to the Karakorum Range in the east. In the south the Frontier runs eastward from Kâpisâ along the bottomlands of the Kâbul River basin, as far as the Indus River. In the higher southern slopes along one portion of the Frontier's northern edge lie the Nuristani languages, which form a third phylogenetic group of the Indo-Iranian languages. The region's languages appear on the Linguistic Map; their phylogenetic classification appears in the Table of Languages. Languages that I have personally investigated include:
Looking for the phonological processes that underlie the region's accentual variety, I find at the base two processes of the larynx: Front Tensing and Back Tensing. The front and back tensing of the larynx during these processes has been determined from acoustic, visual, and proprioceptive observations of speech; but the absence of more sophisticated observational techniques in the difficult field conditions of the region leaves the precise anatomical nature of these tensing processes undetermined. These processes are not mutually exclusive; both forms of tensing may occur simultaneously, as in the region's Indo-Aryan languages.
Front Tensing is a forward and upward pulling of the larynx during phonation, sometimes with a degree of concomitant Anterior Voicing 2. This process produces a raised pitch. The tensing may be strengthened to produce a higher pitched accented phonation, which in the Iranian languages and Khow`ar may be augmented by tighter Anterior Voicing. Front Tensing is used for accented phonation throughout the area, and it is used for normal (unaccented) phonation in the Iranian and Nuristani languages.
Back Tensing is a backward and downward pulling of the larynx during phonation, sometimes with a degree of concomitant Posterior Voicing. This process appears to enlarge the laryngeal cavity, producing a slight megaphonic effect. In the absence of Front Tensing it produces a falling pitch, and it restricts the pitch-raising effect of accented Front-Tensed phonation, producing a narrow pitch-range between accented and unaccented vowels. When strengthened, Back Tensing spreads to the glottis to produce the Whispery Voice of the traditionally-called "voiced aspirate" consonants. Some degree of Back Tensing during phonation occurs in all the Indo-Aryan languages of the Frontier, but Back Tensing is lacking in the Iranian and Nuristani languages.
In the Indo-Aryan languages of the region the strength ratio of Back to Front Tensing varies among the languages: in Açharêtâ' Back Tensing predominates, in Khow`ar Front Tensing predominates, in the remainder both processes are equally evident.
Thus, in Açharêtâ' Back Tensing strengthens slightly over utterance segments, producing a characteristic step-down lowering of the Fundamental Frequency (F0) over the length of an utterance. In Açharêtâ' words with Ending-Accent such strengthening over a long vowel produces a falling-rising pitch across the vowel, which contrasts with the falling pitch across a long vowel in a word with Beginning-Accent (e.g., ending-accented râ't 'night and day' [24-hour period] vs. beginning-accented r'ât 'blood'; details here).
In Khow`ar Back-Tensing is an accentual process that contrasts with the more common Front-Tensing accentuation, producing contrasts such as Back-Tensed dón 'ghee', with rising tone, vs. Front-Tensed dòn 'tooth', with falling tone. Unaccented phonation in Khow`ar is typically strongly Front-Tensed, with Anterior Voicing.
To summarize, Front and Back laryngeal tensing have the following distribution:
In the languages without predominating Back Tensing (i.e., those except the SiNâ' dialects), there are typically three pitch levels in an utterance-final accented span, in a 2 3 1 sequence, representing a Normal-Strengthened-Weakened pattern of delimiting a declaration through a terminal intonational contour. Among groups of these languages the intervals and contours of the pitch levels differ, giving a distinctive accentual quality to each group. The intervals are narrowest in the Southern Group of the Nuristâni languages, the group with historically longer proximity to the Indo-Aryan languages. The intervals widen among the Northern Nuristâni Group and Khowàr, and they are widest in Fârsi. In KalaSa-mun an accented syllable has a somewhat prolonged falling pitch, while in the other languages the post-accentual drop in pitch is abrupt.
1 I follow my mentor Georg Morgenstierne's use of the term "Indo-Iranian Frontier Languages" (e.g., 1929b) to denote the languages of the region.
2 I follow Catford's ( 1977: 99ff.) nomenclature of phonation types.