'Mexican' Isn't a language, you know ;P 'Dialects' of Spanish can be recognized by key words and structure sentence... But mostly by the words used. For instance, in South america, if you're referring to 'buddy, man, dude, etc', in Chile you could hear 'compadre', in Argentina 'pibe', and in Mexico 'cuate'. Now about Italian, when you know a language, it's easy to know when you're not seeing YOURS language, isn't it? Still, things to keep in mind is, Italians use a lot the vowel i. Also they use a lot more the LL and Z in their words.

Mexican; We never use the normal future, we used for speaking all the time the verb go in gerund, another is the sound of s, we used a very soft sound for s, z, and c, spanicher used s the same, but a z they pronounce like tz, und the second person they used vos and vosotros, and they speak a little more strong sound like mexicans. Italian is different is more laughing, and they have many vucals longs, and they used another sounds for letters like Bocaccio, ccio they pronounce like chimney chi. Mexicans have many words with X. I think this are very big differences in general., I hope I could help you

the countries in south america ussually speak in spanish, but no in brasil, cause the native language is the portuguese, mexican is the denomination for the people´s from mexico, also like the colombian, puerto rican, panameño(panama), venezolano(venezuela), the italian is the landuage cause, just in this part of the world, u can find the person who speak italian, so, in mexico talk spanish, that´s all

oh and to kylecito: actually cuate is used more in the center there is a lot of different words to say buddy or man or whatever like morro, tipo, wey, chamaco, etc. etc.

Spanish is the language but mexican is not a language it's the way people speak spanish in mexico like when you say "you" we say "tu" and not "vos". You can tell by the pronunciation like Patricia mentioned it. and I think Italian is very but very different from spanish I'm Mexican so I can tell you that I don't understand a lot of italian although there are similarities