For feminine nouns, we use "la" for singular and "le" for plural (like you wrote: "la pizza" / "le pizze"). "La" is rendered as l + apostrophe when the noun begin with a vowel (for example: "l'amica"), while "le" doesn't change ("le amiche"). For masculine nouns, it depends on the letter they begin with: - If it is a vowel, it works like above and we use l + apostrophe ("l'uomo"). - We use "lo" for nouns that begin with s + consonant, gn, x, y, z, pn and ps ("lo struzzo", "lo gnomo", "lo xylofono", "lo zoo", "lo psicologo") - Otherwise we use "il" ("il libro", "il telefono"). The plural of "l'/lo" is "gli" ("l'uomo" / "gli uomini", "lo struzzo" / "gli struzzi") The plural of "il" is "i" ("il libro" / "i libri") > Are all nouns ending in an "o" pluralized into the "i" form and do all nouns ending with an "a" end with "e" in the plural form? Actually there are some exceptions. For example, "problema", although ending in -a, is a masculine noun and its plural is "problemi" ("il problema" / "i problemi").

Hi! I would like to answer your question so that I also can ask something about your English... ;) As for your question, the answer is: no, that pattern is just the regular one. It is valid in 70% of cases, but there are quite a few exceptions. These exceptions are, for example: 1) nouns which are uncountable so that it's impossible to make the plural: l'orgoglio, l'aglio, la stasi, l'afa, il nuoto 2) nouns which don't change their spelling at all, even thought they could be either singular or plural (in this case you can tell it by looking at the article, 'cause it changes into singular or plural following the regular pattern): IL fermacarte - I fermacarte, and the same goes with la possibilità, le avversità (and most of the similar "tà" words), l'estasi, le stimmate 3) nouns which are masculine but they end with A (as Tano was saying), or with E like L'idioma, IL problema, L'amore, IL pane 4) nouns which are feminine but they end with O for the singular and with I for the plural: LA mano - LE mani 5) nouns which are masculine and follow the pattern: Singular with E - Plural with I, like: IL primate - I primati, IL cardine - I cardini 6) nouns which are feminine and follow the same pattern: Singular with E - Plural with I, like in the case of L'abitudine - LE abitudini, LA luce - LE luci 7) nouns which change MORE than just one letter, from singular to plural: IL DIO - GLI DEI 8) nouns which change gender from singular to plural: L'uovo, IL gregge [Singular/Masculine] - LE uova, LE greggi [Plural/Feminine] 9) nouns which have more than one plural with different genders, depending on their meaning or their use: IL frutto [S/M] -> I frutti OR LA frutta [P/M OR F] || L'orecchio [S/M] -> GLI orecchi OR LE orecchie [P/M OR F] || IL membro [S/M] -> I membri OR LE membra [P/M OR F] My question for you is: What do you mean by "My question IS JUST BY CHOOSING any group of nouns let's say: "? I don't understand this particular use of the word "by".