How to predict the pronunciation of the letters "b", "v", and "h"?

Question

I have learnt that in Spanish, the "b" and "v" have similar pronunciations, and their pronunciation depends on their position in the word. In the beginning of a word, or after an "m" or an "n", the pronunciation is close to the "b" sound, while between two vowels, the pronunciation is close to the "v" sound.

Also, the "h" is silent in Spanish.

But, I have heard some words violating this rule. "Verano" pronounces it like "v" only. And a few cognates do pronounce the "h". I cannot understand why these words violate the rule.

Answer 1

Spanish b and v do not represent different sounds. For the purposes of pronunciation, you can imagine that every v is a b (and nv is mb). A long time ago (before the year 1500 more or less) these two letters did represent different sounds, similar to b and v in English, but that is not so today.

The sound that these letters represent can vary. At the beginning of an utterance, such as when you begin a new word after a pause, the sound is like the English b, or in phonetic spelling, [b]. It's a complete closure of the lips followed by a sudden opening. This sound also appears after [m] (remember nv is read as [mb]). So for example un beso is pronounced [umbeso]; un vaso is pronounced [umbaso].

In every other position, the sound is a fricative, [β], or an approximant, [β̞]. This means the lips come very close to each other but don't touch, and the air goes out between them either with audible friction (like blowing a candle) or without it. This sound is what you might be perceiving as similar to the English [v] sound.

Verano is a completely regular word in this regard. Generally the v will be fricative, [β], after [l], so for example el verano is pronounced [elβeɾano], and it's always fricative after vowels, so if you say hermoso verano without pausing between the words, it will be [eɾmoso βeɾano]. You will likely only hear a stop, [b] as in English, after the indefinite article: un verano = [umbeɾano].

Some people might actually pronounce a [v]. For a native Spanish speaker, this sound is not easily distinguishable from [b] or [β]. Since there are no pairs of words like English bat and vat, which are distinguished by these sounds, a Spanish speaker will not notice the difference, or will only find the sound a bit strange.

As for h, the letter is always silent in native Spanish words, unless it appears in the digraph ch (which is pronounced as in English). Since there are a lot of borrowed and well-known English words with sh, Spanish speakers also tend to read sh as in English. Spanish speakers often know how English h is pronounced, so in proper names and some borrowed words they will pronounce it as they can, which is usually substituting the sound [x] (the velar fricative sound of our letter j).

Answer 2

There are some variations between accents, so you’ll have to be more specific (e.g. link to audio) to know exactly why what you hear isn’t what you expect.

However, there is one point that I think may help clarify something for you. You wrote “in the beginning of a word, or after an ‘m’". It’s actually not about whether the b/v is at the start of a word. It’s about whether it’s at the start of an entire utterance (or maybe in some contexts, the start of a phrase). After a closely linked preceding word that doesn’t end in n, such as de, el or la, a b or v at the start of a word is pronounced weakly (as a fricative or approximant, written [β] in the IPA), not as the plosive [b]. Since Verano is rarely the first word in an utterance, I think you’ll tend to hear it with [β] most of the time, but you should be able to find examples where it sounds like [b] in a context like en verano or un verano.