What do we mean by 'stress' in alliterative verse?

Ordinarily, stress is the thing that makes you look like this.

Fortunately, this is the other kind of stress.

Although unconsciously we all perceive stress, it sometimes takes a little while to get used to consciously identifying stressed syllables, so here are three different ways of thinking about it to help you--see what works best for you.

The phonetic description

Heavily stressed syllables in English are distinguished by being

higher in pitch
louder
characterised by a wider range of vowel-sounds

Try saying, out loud, 'Rosencrantz and Guildenstern are dead', and then 'Rosencrantz and Guildenstern are dead, emphasising the and (click here to hear Alaric saying them if you like). When you emphasise and, you're making it heavily stressed. Say both sentences again, and listen to how and sounds different when you stress it. The pitch rises and you say it more loudly. The sounds change too: when unstressed and comes out as [ən], with a pretty indistinct vowel; when stressed, it comes out as [æn] or [ænd]: the vowel becomes more distinctive.

Just to practice that again, try saying 'Rosencrantz and Guildenstern are dead', and then 'Rosencrantz and Guildenstern dead', emphasising the are (click here to listen to Alaric doing it). Again, listen for the differences, and particularly the change of the sounds in are from [ə] to [ɑ:].

The grammatical description

Most of the time, the root (main) syllables of English words are consistently stressed in the same way depending on the kind of word they're in. Listing the most heavily stressed first:

1. stressed syllables of nouns, adjectives, participles and infinitives.
2. finite verbs and most adverbs.
3. prepositions, conjunctions, articles, parts of the verb to be, pronouns.

Parts of words not belonging to the root, like the -ed of wanted or the -es of fishes, usually join the other clutter down at level 3.

This ranking doesn't always work (either in Middle English or modern)--so in the phrase 'Rosencrantz and Guildenstern are dead', you could put stress on and (a conjunction, usually on the bottom rung of the stress ladder) if you were emphasising that they were BOTH dead. But it does work the vast majority of the time. Thus in the sentence 'Piers shot his dog', Piers (a noun) is heavily stressed, shot (a finite verb) is less heavily stressed, his (a pronoun) is hardly stressed at all, and dog (noun) is heavily stressed. Since heavily stressed syllables are higher in pitch than unstressed syllables, this gives the sentence a melody whereby the pitch falls from Piers to shot, and again to his, and then rises with dog.

Pretend you're Eminem

Try saying 'but on a May morning on Malvern Hills' waving your hands about like Eminem or Snoop Dogg. You'll find you're moving with the stressed syllables: 'but on a MAY MORning on MALvern HILLS'. Try Emineming on any other syllable, and you'll find it's really hard!