Numbami (also known as Siboma or Sipoma) is an Austronesian language spoken by about 200 people with ties to a single village in Morobe Province, Papua New Guinea.

Voiceless /s/ is a fricative, but its voiced and prenasalized equivalents are affricated, varying between more alveolar [(n)dz] and more palatalized [(n)dʒ].

Although Numbami is phonologically conservative, it retains very little productive morphology, most of it related to person and number marking.

In most cases, subject prefixes are easily segmentable from verb stems, but in a few very high frequency cases, prefix-final vowels merge with verb-initial vowels to yield irregularly inflected forms, as in the following paradigm: wani (< wa-ani) '1SG-eat', woni (< u-ani) '2SG-eat', weni (< i-ani) '3SG-eat', tani (< ta-ani) '1PLINCL-eat', mani (< ma-ani) '1PLEXCL-eat', moni (< mu-ani) '2PL-eat', teni (< ti-ani) '3PL-eat'.

The suffix -a(n)dala is unique to ideophones but is clearly related to the word andalowa 'path, way, road' (POc *jalan).

The basic word order in Numbami is SVO, with prepositions, preposed genitives, postposed adjectives and relative clauses.

'ma-1PL.EXCLkiputbanifoodmanuwhichma-1PL.EXCLyakiparenaRELsuintoulaŋapotma- ki bani manu ma- yaki na su ulaŋa1PL.EXCL put food which 1PL.EXCL pare REL into pot'We (excl.)

Genitive possessor nouns precede their head nouns, with an intervening possessive marker that distinguishes singular (na) from plural (ndi) possessors: wuwu na lau 'the leaves of the (generic) betel pepper plant; particular betel pepper plant's leaf'; kapala na lalo 'the insides of (generic) houses; the inside of a particular house'; Siasi ndi gutu 'the Siassi Islands; islands belonging to a particular group of Siassi people'; bumewe ndi bani 'food typically eaten by whites; food belonging to a particular group of whites'.

Attributive genitives resemble possessive genitives except that (1) the modifiers follow their heads, and (2) the "possessors" are nonreferential except in a generic sense, that is, they "never refer to a particular subset of the set they name" (Bradshaw 1982a:128): wuwu weni na 'forest (wild) betel pepper', wuwu Buzina ndi 'type of betel pepper associated with the Buzina people at Salamaua', walabeŋa tamtamoŋa na 'fish poison, native means of stunning fish', walabeŋa bumewe na 'explosives, European means of stunning fish'.

'waandaiya2SGnu-FUT.2SGkiputyawifireni-FUT.3SGsoloŋaenterwa aiya nu- ki yawi ni- soloŋaand 2SG FUT.2SG put fire FUT.3SG enter'And you'll set it afire.

'takalamatodayiluwa1DU.EXCLma-1PL.EXCLyoŋgoseeataselfi-3SGwetecount-maADVkotenottakalama iluwa ma- yoŋgo ata i- wete -ma kotetoday 1DU.EXCL 1PL.EXCL see self 3SG count ADV not'Nowadays, we two don't see each other very regularly.'