Sarvadarshanasangraha 13.42

13.42

vibhaktyanteṣv eva varṇeṣu suptiṅantaṃ padam iti pāṇininā te vibhaktyantāḥ padam iti gautamena ca padasaṃjñāyā vihitatvāt saṃketagraheṇānugrahavaśād varṇeṣv eva padabuddhir bhaviṣyati/ tarhi sara ity etasmin pade yāvanto varṇās tāvanta eva rasa ity atrāpi/ evaṃ vanaṃ navaṃ nadī dīnā rāmo māro rājā jāretyādiṣv arthabhedapratītir na syād iti cen

The truth is, that, as Pāṇini (i. 4, 14) and Gotama (Sūt. ii. 123) both lay it down that letters only then form a word when they have an affix at the end, it is the letters which convey the word's meaning through the apprehension of the conventional association of ideas which they help.[19] If you object that as there are the same letters in rasa as in sara, in nava as in vana, in dīnā as in nadī, in māra as in rāma, in rāja as in jāra, &c., these several pairs of words would not convey a different meaning, we reply that the difference in the order of the letters will produce a difference in the meaning. This has been said by Tautātita—