Oh Mistress Mine: This song is sung by the Clowne in Twelfth Night in Act II, Scene 3. He sings after being encouraged to do so by the other characters. The song is a man encouraging his lover to enjoy the present and stop searching for love elsewhere. Within it conveys feelings of carpe diem, living in the moment, and taking advantage of one's youth. 

French Scene 1: This scene was originally Act II Scene 3, but we chose to place it earlier so that the scenery only has to transition from the Court into the Forest of Arden one time.

comely: becoming, praiseworthy

envenoms: poisons

where you use to lye: does not mean "where you used to sleep" (in the past) but "where you are in the habit of sleeping"

butcherie: slaughterhouse

boisterous: violent, unruly

Crownes: gold coins; four crownes = £1 (pound) or = $1.22; a thousand crowns would be about 9 month salary for a laborer, and 500 crownes half of that (4.5 months salary), so this would be a sufficient amount for them to run away and live off for a month, maybe multiple if they're smart, which is a large amount for a domestic servant like Adam to have saved, but is not a large sum to last for an extended time between the two of them.

he that doth the Ravens feed: God "giveth to the beast his food, and to the young ravens which cry" (Psalm 147:9); "Consider the ravens, for they neither sow not reape, which neither have storehouse nor barnes, and God feedeth them: How much more are yee better then the foules." (Luke 12:24)  

providently caters for the Sparrow: "Are not five sparrowes solde for two fartherings, and not one of them is forgotten before God" (Luke 12:6); in giving all he has to Orlando, Adam has faith that 'providence' (God's divine care) will supply his 'providence' (food, sustenance)

lustie: vigorous, healthy

antique: ancient

content: this is the same rhyme scheme Celia uses at the end of Act I French Scene 15, the audience would expect this to signal the end of the scene, but Adam continues with his monologue affirming his devotion to Orlando. This reinforces the meaning of the words: that Adam will never leave Orlando come what may. Adam finally signals the end of the scene with a feminine (two-syllable) rhyme (see below).

thee: encouraged by Orlando's response, Adam now refers to Orlando with the familiar term.

seaventeene: In some editions, this has been listed as seventy years, but it makes more sense with this correction which other editors have made (Shakespeare is historically bad at math and numbers in his plays). From the age of seventeen, Adam has worked for this same family and lived here, almost fourscore (80) years. At seventeen, he might have left to seek his fortunes much like Orlando does now at a similar age, but now it is too late to embark on the adventure Orlando is going on. 

too late a week: equivalent to 'too late a day', it is much too late for Adam to seek his own fortune

not my sovereigns debter: Though it isn't the smartest idea for Adam to embark on this journey at his age, he would rather die at peace, free from indebted service to Oliver. This two syllable rhyme is known as a feminine rhyme and finally signals the end of the scene, after Orlando originally cued a possible end with the earlier rhyme (see "content" above). The variation in the rhyme ending shows Adam's independence, even as he devotes himself to Orlando, he is doing so of his own agency and choice.