a double vowel is always 'long'
(de) slaap
('sleep') -
(de) vloot2 ('fleet')
a single vowel at the end of a word is always 'long' (except E)
(de) sla
('lettuce') -
(de) vlo2
('flea') -
de2 ('the' #1)
a single vowel followed by one or more consonants at the end of
a word is 'short'
slap
('weak') -
(het) vlot23 ('raft')
a single vowel followed by one consonant followed by another
vowel is 'long.' (The syllables split is before the single
consonant.
This is somewhat like English 'silent E')
slapen (sla-pen)
('to sleep)
vloten (vlo-ten)2 ('fleets')
a single vowel followed by two or more consonants is 'short.'
(The syllable break is between the consonants)
slappe (slap-pe)
('weak') -
vlotten (vlot-ten)23 ('rafts')
This rule 'works' for double consonants, but not always when the
consonants are different
Diphthongs don't have 'short' and 'long' forms
So (de) man2
('man, human adult male) has the plural
mannen (man-nen)2
while (de) maan2
('moon')
has the plural manen (ma-nen)23