Bilingualism is touted as bestowing special abilities like easier multitasking. Most recently Ellen Bialystok has said regular use of two languages can help delay Alzheimer's. http://www.nytimes.com/2011/05/31/science/31conversation.html?_r=1
For me, being bilingual meant I knew Latvian without ever conjugating a verb or poring over long vocabulary lists. It meant that when I arrived at the airport in Riga the customs officer asked if I was from Latgale (my mother's province) though I had never set foot in Latvia before.
And my bilingual Latvian brain colored my world. There are plants I know the names of only in Latvian and animals are always named in the diminuitive. All nature is still infused with spirit since Latvia was Christianized in the 13th century after it replaced a pervasive animism.
So I could have posted an essay on the theme but I've been going through an old leather covered notebook (the gift from Eulalia in Spain, the hatmaker and singularly strong woman).
The Straits of Melaka
The straits churn up
porcelin vases, Japanese mortar
onto the crystal calm
of a kampung beach.
Straight ahead lies Sumatra,
behind, the centuries
reminise on each street
in many tongues.
burn in an oil lamp
brought up to bed each night.