nonsense speech
Expressions that retain the basic structure of a language in terms of sound and meaning but replace meaningful content words (e.g., nouns, verbs) with plausible pseudo-words. Nonsense speech is also referred to as “pseudo-utterances”."Reference: M. D. Pell, L. Monetta, S. Paulmann, and S. A. Kotz, “Recognizing Emotions in a Foreign Language,” J Nonverbal Behav, vol. 33, no. 2, pp. 107–120, 2009, doi: 10.1007/s10919-008-0065-7.