I'll keep adding 'easy notes'. :)
Dropping
Note 1:
Spanish drops initial f's followed by a vowel, writing an h instead. The rule is not followed in diphthongs or before l/r.
Spanish: harina, hijo, hoja, humo but fuego, fuente, flor
Portuguese: farinha, filho, folha, fumo, fogo, fonte, flor
Catalan: farina, fill, fulla, fum, foc, font, flor
French: farine, fils, feuille, fumée, feu, fontaine, fleur
Italian: farina, figlio, foglia, fumo, fuoco, fontana, fiore
Romanian: făină, fiu, foaie, fum, foc, fântână, floare
Note 2:
French drops many s's, writing a circumflex accent upon the preceding vowel instead.
French: hôpital, coûter, château, fête
Portuguese: hospital, custar, castelo, festa
Spanish: hospital, costar, castillo, fiesta
Catalan: hospital, costar, castell, festa
Italian: ospedale, costare, castello, festa
Romanian: spital, a costa, castel, -