why w and y are called semi vowels
Semivowel In phonetics and phonology, a semivowel or glide, also known as a non-syllabic vocoid, is a sound that is phonetically similar to a vowel sound but functions as the syllable boundary, rather than as the nucleus of a syllable.[1] Examples of semivowels in English are the consonants y and w, in yes and west. Written /j w/ in IPA, y and w are near to the vowels ee and oo in seen and moon, written /iː uː/ in IPA.
Ñ Ñ (lower case ñ, Spanish: eñe, Phonetic Alphabet: /ˈeɲe/ "énye",  pronunciation (help·info)) is a letter of the modern Latin alphabet, formed by placing a tilde (called a virgulilla in Spanish) on top of an upper- or lowercase N.[1] It became part of the Spanish alphabet in the eighteenth century when it was first formally defined, but it is also used in other languages such as Galician, Asturian, the Aragonese Grafía de Uesca, Basque, Chavacano, Filipino, Chamorro, Guarani, Quechua, Mapudungun, Mandinka, and Tetum alphabets, as well as in Latin transliteration of Tocharian and Sanskrit, where it represents [ɲ]. It represents [ŋ] in Crimean Tatar. In Breton and in Rohingya, it denotes nasalization of the preceding vowel.