Language is the star of Love's Labour's Lost, and by far the most important tool of characterization in the play. The noblemen and women take pride in their ability to craft arguments, images, and zing comebacks and insults. Dull and Costard, the rustics, continually use malapropisms (using the wrong word in place of another). They absorb the intellectual atmosphere and try to fit in. When Costard receives remuneration (payment for services) from Armado for carrying his poem, he mistakes the word, crying "Remuneration! O, that's the Latin word for three farthings. Three farthings- Remuneration" (3.1.59). When he earns a guerdon – more money – from the wealthier Berowne, he delights: "Gardon, O sweet gardon! better than remuneration; a 'leven-pence farthing better; most sweet gardon!"
Holofernes can't keep himself from talking like a teacher, in Latin, with lists of synonyms after every word. And Armado, oh Armado. The braggart habitually asks rhetorical questions to flesh out his speeches and letters. Take a look at "Writing Style" for more specifics on linguistic conventions Shakespeare uses.
A word about verse and prose. You'll notice that sometimes Shakespeare writes in lines (rhymed or not) like a poem – that's verse. Usually it's in iambic pentameter – five feet of an unstressed and stressed syllable. If you exaggerate, it sounds like this: da DUM da DUM da DUM da DUM da DUM. Here's a cute couplet – two rhymed lines – that demonstrates what we're talking about:
PRINCESS: Sweet health and fair desires consort your Grace!
KING: Thy own wish I thee in every place. (2.1.52-53)
Sometimes the Bard writes in paragraphs, in prose. It's often the case that the more educated characters speak in verse, the less educated in prose. But there are exceptions, which often clue us in to the character's emotional state. When Berowne first discovers his love for Rosaline, he is so unnerved and excited that he delivers a scattered paragraph in prose.
Two social worlds are at play here. There's the court, including the King and his men, the Princess with her ladies and Boyet. And there's the village that includes: Costard, Jaquenetta, Holofernes, Nathaniel and Dull. Armado – guest of the King, pursuer of Jaquenetta, rival of Costard, and theatrical collaborator of Holofernes – is somewhere in between. As in other Shakespearean plays, the noble and rustic worlds influence each other. Costard's letter delivery mix-up eventually frees the noblemen to openly pursue their crushes. The King's commission of the Nine Worthies pageant brings about Armado's "engagement" to Jaquenetta. Mostly, the juxtaposition of these two worlds creates a complex picture of human love, from the physical love of Costard and Jaquenetta, to the austere challenge posed by the Princess.
How characters handle their desire is roughly predictable along class and gender lines. The neurotic noblemen overanalyze and fret about their love. What should they do? How can they keep their feelings from their friends? Should they compare their lover to the moon or to the sun? The women are more stoic and cautious. They show evidence of crushes to each other, but not to the men until the very end of the play. The rustics don't harbor the same hang-ups about love and just go for it. Costard and Armado are both attracted to Jaquenetta, who ends up two months pregnant by the end of the play. We're not sure who the father really is, but Armado gets pinned.