Expressive aphasia refers to difficulty in:

Expressive aphasia is a condition that affects a person's ability to communicate their thoughts through speech or writing. This type of aphasia typically occurs when there is damage to the part of the brain responsible for language production, often the Broca's area in the frontal lobe. Individuals with expressive aphasia may have a good understanding of language but struggle significantly when trying to articulate their words or construct sentences. Therefore, the correct answer focuses on the difficulty in sending out thoughts, which accurately reflects the primary challenge faced by those with this condition.

In contrast, understanding spoken language would indicate a different type of communication challenge often seen in receptive aphasia. Reading comprehension is also more related to receptive language capabilities, while maintaining attention pertains to cognitive focus rather than language abilities.