Sounding like a disease, the word synalepha means that two vowels merge at the juncture of words. Any two by-standing vowels merge into one: either one of the vowels is omitted, or a diphthong appears:
Ana abre = Ana_abre [an`abre] – Ana opens (the door)
Hay agua = Hay_agua [a`jagwa] – We`ve got water
A diphthong also appears when the conjunction y ("and") is next to a vowel:
Ana y Elena = Ana y_Elena [`ana je`lena]
Synalepha is a foe of all Spanish learners: it makes the word boundary unrecognizable, and the speech incomprehensible. To learn to hear words in the speech, one should learn to read them correctly, just like the Spanish.