When does acute change to grave?

[minus273]

On Pharr page 4:
κᾱλαὶ βουλαὶ ἦσαν φίλαι
and
δεινὴ κλαγγὴ ἦν ἐν Χρύσῃ κᾱλῃ
why graves here?

[chad]

hi see pharr s550.

[minus273]

But I haven't see any oxytones here.
βουλαὶ is graved. So is κλαγγὴ.
And esan is circumflex, philai's acute is not on the last syllable.
WHY...

[chad]

hi, boulai/ and klaggh/ are oxytones. in a sentence, the acute accents will turn into graves, other than in the situations set out in pharr s550.

watch the accents here:

boulai\ kai\ klaggh/.
klaggh\ kai\ boulai/.

it has to do with sound. the highest pitch in each of these sentences is the last syllable. the pitch in these sentences goes up up up &c to the end.

the grave accent warns you that the next syllable (in the next word) will be on a higher pitch. the acute is the opposite, it warns you that the next syllable will drop to a lower pitch.

[minus273]

Oh, got it. Methought oxytones change oxytones before itself to grave...