אֶת־עַ֥ם נוֹעָ֖ז לֹ֣א תִרְאֶ֑ה עַ֣ם עִמְקֵ֤י שָׂפָה֙ מִשְּׁמ֔וֹעַ נִלְעַ֥ג לָשׁ֖וֹן אֵ֥ין בִּינָֽה׃
No verás á aquel pueblo espantable, pueblo de lengua oscura de entender, de lengua tartamuda que no comprendas.
Rashi
a people of a strange tongue With another language, which is not the Holy Tongue. A similar expression is (Isa. 33:19): “A people of a strange tongue you shall not see, a people of speech too obscure, etc.” The “nun” and the “lammed” are interchangeable, like נִשְׁכָּה, chamber, which is [equivalent to] לִשְׁכָּה, in the Book of Ezra (Neh. 13:7).