yadā tu bāhyavastuni pratyasto bhavati tadā tasmin pratipattā bāhyatayā viparyastaṃ kriyāsādhanasāmarthyaṃ tasya manyata iti bhavati śabdārthaḥ
However, when [the mental form] becomes superimposed on an external object, then the cognizer, being influenced by its external character, considers it as capable of accomplishing action, and thus it becomes denoted by words.