Which of the following is a characteristic of speech disorders?

A characteristic of speech disorders is indeed difficulty forming sounds or words. This can manifest as articulation problems, where an individual has challenges pronouncing sounds correctly, or fluency issues such as stuttering, which affects the flow of speech. Speech disorders specifically relate to the physical production of speech, including the ability to manage the movements required to produce sounds and words.

The other options address different areas of communication and cognitive functioning. The inability to understand the meaning of words relates to language disorders, which involve difficulties with comprehension rather than speech production. Problems with attention and hyperactivity are more associated with attention-deficit/hyperactivity disorder (ADHD) and do not specifically pertain to speech disorders. Neurological differences in brain structure might influence a variety of disabilities, but they do not directly define characteristics of speech disorders themselves; rather, they could impact various aspects of learning and communication more broadly.