Four rules: two spellings, one letter
The first two are really one rule: ll and y before a vowel are the same sound. The third is y's other identity; the fourth is ñ.
The number after each row is how many corpus words matched — a small sample, which is why the examples are recorded separately (click to hear). One row shows 0: not because that type is rare (rey, hoy, muy are common words) but because this corpus happens not to use it.
One sound, not two l's. The tongue rises near the hard palate leaving a narrow gap, vocal folds on — close to the y of “yes”, but more fricative.
Identical to ll. Almost everywhere yo and llo begin with the same sound — the most widespread merger in Spanish.
Here y is the vowel [i], the same as the second half of “ei”: rey is [rei], not a drawn-out [rej].
One sound: the whole tongue blade against the hard palate, air out through the nose. “ni” + “ya” is two sounds; ñ is one.
Why they merged
ll used to be [ʎ], a “y with a lateral”
Latin ll was a lateral palatal ([ʎ]): tongue tip against the hard palate, air escaping around the sides. It differs from the fricative [ʝ] by very little, and that little was worn away over the centuries — most regions no longer distinguish them. The merger is called yeísmo.
The merger creates homophones
Different spelling, same sound: valla (fence) / vaya (go) / baya (berry) are one sound. So are calló and cayó. They are grouped below so you can hear each one.
y's second identity: the vowel [i]
Word-finally (rey, hoy, muy) or as the conjunction (y = and), y is a vowel, [i]. So rey sounds like rei, not a drawn-out [rej].
One ll, three regional readings
These are not three phonemes but one thing realised differently. Spanish spelling does not encode the difference — someone writing llave may say any of the three.
Most regions (southern Spain, most of Latin America)
llave begins exactly like yo — here ll and y are one and the same sound.
Northern Spain, parts of the Andes (disappearing)
ll is a lateral: the tongue tip touches the hard palate and air escapes around the sides, while y is a fricative. Two different sounds.
Argentina, Uruguay (sheísmo)
yo sounds like “sho”, llave like “shave”.
Different spelling, same sound
Every group below sounds identical — the hardest evidence for yeísmo, and the reason “ll written as y” is such a common Spanish spelling error.
Three places Mandarin speakers slip
Reading ll as [l]
llave becomes “la-ve”. English has l, so two l's read as one — but ll is a fricative with the tongue near the hard palate, nothing like l. The y in yes is a much better reference.
Splitting ñ into two sounds
año becomes “an-yo”. ñ is the whole tongue blade against the hard palate (not the tip), air entirely through the nose: one gesture, one syllable.
Stretching a final y into a glide
rey becomes [rej] (like English ray, but tighter). Here y is the vowel [i], identical to rei.
The numbers on this page
Rules: all four are facts of Spanish orthography and phonology, and need no measurement. The ll/y merger has a name (yeísmo); it is not this page's invention.
Examples: 24 words, each recorded on its own; the homophone section adds 5 groups.
Corpus: 26 words containing ll / y / ñ (ll 9, y + vowel 5, final y 0, ñ 12). A small sample, not a distribution.