According to Hudson (1978:23), it is possible that the Land Dayak languages form a subgroup with the Rejang-Baram languages, as some of the Land Dayak languages (Ribun, Pandu, Sanggau, Jongkang and Semandang) have an intervocalic k in their reflexes for ‘two’ (cf. dukah or dukoh). This corresponds to the intervocalic stop in the word for two in some of the Rejang-Baram languages (cf. [de]gwa]). Blust (1981) classifies Land Dayak languages in one subgroup with Malayic, Sundanese, Rejang, Tamanic (Embaloh), Acehnese and Chamic on the basis of some lexical agreements (especially in the numerals). However, Land Dayak languages are morphosyntactically rather different from Malayic (and other Austronesian) languages. If their lexicons have much in common with the Malayic languages, this might just as well be the result of borrowing, as on the whole these lexicons seem to reflect different sets of sound correspondences vis-à -vis PMP.

Although it is evidently far too early to make any sort of inference about the history of Land Dayak, there are some similarities between this group and some of the Orang Asli languages^[13] which are striking enough to be mentioned, and which are certainly a topic for further investigation. One is the presence of a series of nasally released stops, or, as they are also called, “preploded nasals”. I prefer the last term, because it does more justice to the actual phonetic change that has taken place. In Land Dayak, members of the preploded series (-pm, -tn and -kŋ, or, in some languages, -bm, -dn, -gŋ) are formed by uttering a stop without releasing the plosure, and then letting the airstream escape through the nose. In most of the Land Dayak languages, original final nasals became preploded. Compare the following examples from Sungkung, a language spoken in the West Kalimantan regencies of Sambas and Sanggau in a chain of six villages along the Sarawak border:

Proto-Land Dayak^[14] *ŋarVm ‘night’ > Sungkung ŋaləpm ‘id.’

Proto-Land Dayak *madVm ‘rotten’ > Sungkung mad εpm ‘id.’

PMP *Zalan ‘road, path’ > Sungkung alatn ‘id.’

PMP *(lnøipən ‘tooth’ > Sungkung jipətn ‘id.’

PMP *Daqan ‘branch’ > Sungkung da?atn ‘id.’

PMP *qiDuŋ ‘nose’ > Sungkung nukŋ ‘id.’

Proto-Land Dayak *turaŋ ‘condylar bone’ > Sungkung tulakŋ ‘id.’

Preplosion took place in all final nasals, unless the nasal in question was historically preceded by another nasal. Compare:

PMP *[] ənəm ‘six’ > Sungkung nəm ‘id.’

Proto-Land Dayak *ram[i]n ‘house’ > Sungkung amin ‘id.’

Proto-Land Dayak *taŋ an ‘hand’ > Sungkung ta ŋan ‘id.’

N.B.: In the case of nukŋ ‘nose’ (see above), the preploded nasal is preceded by another nasal, but this nasal developed from a historical *(n)D. This *(n)D became a nasal only after preplosion had taken place.

In Orang Asli (“Aslian”) linguistics, preplosion is referred to as “disintegrated nasals” (Skeat and Blagden 1906:772-773) or “predenasalisation” (Benjamin 1985:14; Diffloth 1976:230). It is observed in Central Aslian languages, including Temiar and Semai. These languages also have –jɲ, as they allow palatals in word-final position. As in Land Dayak, their preploded nasals derive historically from simple nasal consonants (Skeat and Blagden 1906:773).

Some examples from Semai (taken from Diffloth 1976):

raŋɔ:jɲ ‘jew’s harp’ (Diffloth 1976:243)

do:kŋ ‘house’ (cf. Old Mon ḍūŋ ‘city, province’; Diffloth 1976:231)

[gmgu:pm] ‘to winnow vertically’ (Diffloth 1976:236) ?ej ɲ (East Semai), ?εɲ

(West Semai) ‘I’

Skeat and Blagden (1906), Benjamin (1985) and Diffloth (1976) do not give exact phonotactic conditions for the occurrence of preploded nasals in Central Aslian, nor do their examples allow any conclusions on this matter. There are some Semai cases where preplosion seems to have been blocked by the occurrence of a preceding nasal (as in Land Dayak and Malayic Dayak languages).

Compare:

sma:ɲ ‘to ask’ (Diffloth 1976:231)

maɲu:ɲ ‘small fruit sp.’ (Diffloth 1976:243)

tuɲεɲ ‘(name of a hill)’ (Diffloth 1976:242)

But there are also cases where preplosion happened in spite of a preceding nasal, and, inversely, there are cases where preplosion did not take place although there is no preceding nasal:

raŋɔ:jɲ ‘jew’s harp’ (Diffloth 1976:243)

turɔ:ɲ ‘the last remaining of a series, e.g. teeth’

Again, as in Land Dayak and Malayic Dayak languages, the preceding nasal in raŋɔ:jɲ may eventually turn out to be a recent development from a stop or a nasal + stop cluster (as in Proto-Land Dayak *hi(n)duŋ ‘nose’ > Sungkung nukŋ, see above). But this is a speculative explanation, and the solution to this question involves a more thoroughgoing comparative historical study of Aslian languages than has been done so far.

Preploded nasals are not uncommon in other languages, but the change of final nasals to nasally released stops seems to be an areal feature which is typical for the languages of mainland Southeast Asia and some parts of Sumatra and Borneo. Preplosion also occurs in some Malay dialects spoken by Orang Asli (Benjamin 1985:14) and in some Malay dialects spoken by the Orang Darat and some of the Orang Utan in the Riau Archipelago (cf. Kähler 1960:36-37, 54-55). It must also have happened in Urak Lawoi’, a Malayic language spoken off the Southwest coast of Thailand. In Urak Lawoi’, -p, -t and -k must have developed from original nasals via a stage of preplosion. From Hogan’s vocabulary (Hogan 1988) it appears that the phonotactic conditions for the development of Urak Lawoi’ -p, -t and -k were rather similar to those applying to preplosion in Land Dayak languages. In Borneo, it is found in many Land Dayak languages, but some have not been affected by it, whereas reversely, some of the other Dayak languages did also develop the series. These other Dayak languages include West and East Barito languages in Central and South Kalimantan, and Malayic languages (such as Salako, Kendayan and varieties of Mualang) in West Kalimantan. The fact that preplosion occurs in Land Dayak languages as well as in Aslian languages is therefore not significant in itself. But it seems to correlate with some lexical similarities between these two language groups. Compare the words for ‘to die’ and ‘to bathe’ in Orang Asli languages (taken from Benjamin 1976, gloss 19 and 132):

Almost all Orang Asli languages exhibit kəbəs or a related form for ‘to die’, and more than half of them have mamuh or a related form for ‘to bathe’. Again, the Central Aslian languages score highest in exhibiting these forms.

Forms like kəbəs and mamuh are also generally used in Land Dayak, where the word for ‘to die’ is moreover related to the words for ‘to kill’ and ‘to sleep’. (This relationship does apparently not exist in the Orang Asli languages.) Compare:

N.B. The forms mane?, mandey?, manI? and man ḯ ? are adaptations of Malay mandi or Malayic Dayak man(d)i?.

The fact that the Aslian languages share preplosion and a similar form for the word for ‘to die’ with (Land) Dayak languages was already pointed out (or hinted upon) by Skeat and Blagden (1906:773 and 435-438).

Generally speaking, similarities as the ones under discussion here may be due to (1) genetic relationship, (2) chance or (3) contact, whether in the form of cultural borrowing or a substratum. A genetic relationship will not account for the similarities, as all other evidence leaves little doubt about the classification of Land Dayak languages as Austronesian, and about the classification of Orang Asli languages as Austro-Asiatic. It would be possible to maintain that the lexical similarities are due to chance, but this seems to be a less suitable explanation for preplosion, the spread of which should be described in terms of an areal feature. If there was contact, this must have been a very long time ago, as there is, as far as I know, no evidence for it in historical times. The nature of the similarities, two rather basic vocabulary items and a phonological areal feature, suggest intimate borrowing. Allowing for the fact that our present knowledge is too scanty to draw any definite conclusion, I tend towards explaining these similarities as the result of language shift. It may have been the case that original Aslian speakers in Borneo shifted from their original language to Land Dayak, whereby few words of the original language, such as the words for ‘to die’ and ‘to bathe’ were maintained and resisted replacement by the well-attested Proto-Austronesian roots *anDuy ‘to bathe’ and *maCey ‘to die’. It is also possible that once there was a third (unknown and now extinct) language spoken in Borneo and on the Malay Peninsula, and that its speakers in Borneo shifted to Land Dayak, while its speakers on the Malay Peninsula shifted to Aslian. Although forms like kəbis and mamuh are quite common in Aslian, at this stage it is not clear whether they are inherited and can be attributed to Proto-Aslian. It therefore remains possible that they are innovative in both Aslian and Land Dayak.

Preplosion is found in many languages that do not belong to the same linguistic subgroup or even the same language family. Both Land Dayak and Aslian have members that have never been affected by it. Preplosion is therefore younger than the splits that led to the emergence of different Austronesian linguistic subgroups such as Malayic Dayak and Land Dayak. It is clearly not diagnostic for language classification in Southeast Asia.