One of the toughest parts of learning Spanish is using the two forms of the verb "to be" correctly: "ser" and "estar".
"Ser" is about the essence of being: I am male, it is possible, you are American. It's the kind of stuff you'd see in the description of someone on the Most Wanted List. "Estar" is for contingent characteristics: I am here, that apple is rotten, we are late.
This was beautifully described Sergi Pámies's column on Spanish for foreigners in El País on 8 August 2003, "Copula, que algo queda." (It's in the archives, but you have to subscribe the on-line paper to get access.) He sums up the differences by recalling a line from a Campoamor poem about the inhabitants of a lunatic asylum: "Ni están todos los que son, ni son todos los que están." My beginner's translation would be: "They don't show everything they are, nor are they everything they appear to be."
One can, of course, speculate endlessly about how this subtlety affects the worldview of Spanish speakers, and whether having to make do with just one verb "to be" makes English speakers less aware of the nature of being. I don't think it makes much difference, really - circumlocutions are the stuff of all languages. However, one might expect that similar distinctions will show up elswhere in the language, and that's indeed what I recently learnt.
In trying to translate "become" into Spanish, I learned that different verbs are used for different kinds of becoming. "Ponerse" (the verb poner, to put, plus the reflexive pronoun "se") is used for temporary but normal changes, like becoming ill, getting angry, or turning pale. "Volverse" (volver means to turn) is use more profound and involuntary changes, like going mad, becoming arrogant, or becoming impatient. One could say that ponerse is to volverse, as estar is to ser.
We see, again, a distinction between the temporary and the permanent, the superficial and the profound.
Still, having just two ways to describe being is as much an approximation as just one. In fact, Spanish uses hacerse and llegar a ser to describe changes in profession and social status (e.g., she became a lawyer), and convertirse and transformarse to talk about changes in essence (e.g., the wine became vinegar).