It’s not purely a mood disorder …
Linking words together based on similar sounds rather than coherent meaning is a symptom of psychosis in people with bipolar disorder.
clang associations in bipolar disorder
It is thought that people begin to speak but become distracted by both the meaning and sound of the words they are using. This means that they repeatedly lose the thread of what they are saying, and shift off the topic to follow the new connections they are making between words.
what is clanging
New ideas and thoughts come so fast that even speaking as rapidly as possible, a patient may be able to express only a small percentage of them.
Disorders of Thought Are Severe Mood Disorders: the Selective Attention Defect in Mania Challenges the Kraepelinian Dichotomy—A Review
Word salad. (Schizophasia) A jumble of words that are not apparently linked and may be hard to understand. Philosopher Noam Chomsky is well known for his studies in language and cognitive science; his famous grammatically correct example of word salad is “Colorless green ideas sleep furiously.”
Disorganization. Jumping from one idea to another without transition.
Neologism. Making up words that have no meaning to anyone but the speaker.
Echolalia. Repeating others’ words or phrases.
Flight of ideas: (in psychiatry) a continuous stream of talk in which the patient switches rapidly from one topic to another and each subject is incoherent and unrelated to the preceding one or is stimulated by some environmental circumstance. The condition is frequently a symptom of acute manic states and schizophrenia.
Mosby’s Medical Dictionary, 8th edition. © 2009, Elsevier.