косноязы́чие

nounneuterinanimateuncountablevery rarely used (#39938)

1.
confused articulation, speech defect, impaired articulation
И́з-за косноязы́чия ему тру́дно выступа́ть пе́ред людьми́.
Because of his speech defect he finds it hard to speak in front of people.
Somewhat bookish; the everyday medical term is «нарушение речи».
2.
inarticulateness, clumsy style, wooden manner of expression
Критики упрека́ли а́втора в косноязы́чии.
Critics reproached the author for his clumsy style.
Of speech or writing: an inability to express oneself clearly and elegantly.

Examples

Косноязычие мальчика беспокоило его учителей.
The boy's speech impediment worried his teachers.
Из-за косноязычия он редко выступает публично.
Because of his speech impediment, he rarely speaks in public.
Его косноязычие мешало ясно выразить мысль.
His inability to express himself clearly made it difficult for him to convey his thoughts.