When two vowels go walking, the first one does the talking

"When two vowels go walking, the first one does the talking" is a spelling rule used when teaching English-speaking children that says that when there are two vowels in a word the first one has the so-called "long" sound of the vowel (or alphabet name), and the second one is not pronounced.

For example, in train the a has the so-called “long” a sound and i does not sound. The same happens for each, die, goat, and rescue.

Unfortunately, this rule is false 60% of the time. Counterexamples: head, chief, pause, out, biscuit.