etad uktaṃ bhavati na kramamātraṃ vācakaṃ, nāpi varṇādhāraṃ, nāpi varṇamātraṃ, kiṃ tarhi---, varṇā eva kramopasṛṣṭā vācakā iti
The meaning is this: neither is mere sequence expressive, nor [sequence] as subsisting in letters, nor letters alone, but rather the letters themselves when accompanied by sequence are expressive