Material symbols (for verbal expression)- The words, gestures and the like which play auxiliary role in the production of the Bhāvaśruta (actual articulate knowledge).
dravyaśrutaṃ - śabdasaṃketādirūpam.
(Jaisidī 2.22 Vṛ)
davvasuyaṃ saṇṇā-vaṃjaṇakkharaṃ, bhāvasuttamiyaraṃ tu...
sajnāksaraṃ, vyanjanākṣarcaṃ vaite dve api bhāvaśrutakāranatvād dravyaśrutaṃ, itarattu labdhyakṣaraṃ bhāvaśrutam.
(ViBhā 467 Vṛ p. 218)
...varṇapadavākyātmakaṃ vacanaṃ paudgalikatvād dravyaśrutam arthajnānātmakasya bhāvaśrutasya sādhanaṃ bhavati.
(Bhikṣu 4.2 Vṛ)
See - Bhāvaśruta.