What is the impairment of the ability to produce words in their correct sequence and with all necessary morphemes called?

The impairment of the ability to produce words in their correct sequence and with all necessary morphemes is referred to as agrammatic. This term is commonly associated with a type of language disorder where individuals struggle to construct grammatically correct sentences. In agrammatism, patients often omit function words such as "is," "and," and "the," and also omit inflections or morphemes that indicate tense or plurality. This results in speech that may be telegraphic or lacking in grammatical completeness.

The identification of agrammatism specifically highlights the challenges in producing language with the correct sequence and required morphemes, which makes it the most accurate descriptor for this impairment. It is essential in differentiating the type of expressive language difficulties a person may experience, particularly in the context of aphasia-related disorders.