Mary has difficulty sounding out words like "though" and "calendar." Her difficulties lie in which of the following aspects of language?

The correct answer focuses on phonology, which pertains to the sounds of speech and the rules governing how these sounds are organized and used within a particular language. In the case of Mary struggling with words like "though" and "calendar," this suggests she has challenges in processing the individual sounds or phonemes that make up these words, particularly in understanding their pronunciation and the patterns in which sounds occur.

Phonological development is critical for developing literacy skills, as it forms the foundation for reading and writing. Mastery of phonological awareness enables individuals to successfully decode new words by sounding them out. Thus, if Mary finds it difficult to sound out certain words, this indicates a phonological issue rather than difficulties in understanding meaning (semantics), structure or form of words (morphology), or the social use of language (pragmatics).