Veṅkaṭanātha discusses in his commentary on PMS 1.1.9 the case of words having multiple meanings. On the one hand, there are words which have multiple meanings and whose meaning can be fixed only due to the proximity to other words. On the other, there are words which have one prevalent meaning, but which can assume a different meaning due to the proximity of other words. Therefore, the proximity of other words is not in itself a disambiguating factor. The Nyāya objector takes advantage of that to suggest that one needs to resort to convention.
A review of our 2013 book on the evolution of the semantics of tantra and prasaṅga by Émilie Aussant can be read on the Journal of South Asian Languages and Linguistics (link here).
Many thanks are due to Dr. Aussant for her ability to explain in a few sentences the broad context (the Sanskrit śāstra tradition and its ability to encode as many aspects of life as possible), the narrow one (metarules for the interpretation of sūtras) and the specific topic of tantra and prasaṅga.
Mīmāṃsā authors refute the Nyāya and Buddhist theory of a conventional relation and try to prove that nobody would ever be able to establish a linguistic convention without words, since any convention-maker would in turn need words to explain that a certain word X is to be connected with a certain meaning. It follows that, in order to avoid a circular regress, at some point one necessarily needs words whose relation with their meanings is not conventional. Later Nyāya authors introduce here the idea of a God who creates words with an embedded conventional relation, but this thesis implies, according to Mīmāṃsā authors, far too many unwarranted assumptions. Mīmāṃsakas rather stick to common experience, in which language is a given.
Mīmāṃsā authors also dedicate much energy to the explanation of the process through which one learns a language, first understanding the meaning of basic sentences and then the meaning of their constituent words.