The sonnet shows that Romeo and Juliet are both familiar with love poetry. They are both smart, and they recognize what the other is doing, so that makes them well matched. By using a sonnet, Shakespeare shows that the two are really in love.
Because a sonnet is a love poem as such, therefore they speak this way to convey a sense of passion and also lust, it is effective as it is a love poem as i mentioned, therefore it is self explanatory
