VOT is that?

Carlos Leiva writes

Could you speak about VOT in your blog next time? Drawing the differences between English and Spanish VOTs?
While smoking a cigarette, I think I found a difference when pronouncing some words. I mean, the smoke came out from my mouth differently, I think.

As a non-smoker, I cannot comment on the second paragraph. And it’s not altogether clear what Mr Leiva is asking for in the first.
Yes, the [p] in English pair is aspirated, i.e. has a long voice onset time (VOT). There is a substantial delay after the lips separate before the vocal folds kick in with voicing. During this time air from the lungs escapes unobstructed through the oral cavity, sounding “like a little [h]”.
The Spanish [p] in perro is unaspirated, i.e. has zero VOT (or a very short VOT). There is very little or no delay between the labial release and the onset of voicing, so no “little [h]”.
Unlike pair, the [p] in English spare is unaspirated.
In words like pray, play, twin, cure the aspiration is manifested in the voicelessness of the liquid or semivowel; but in spray, splay, obscure in principle not (because the [s] inhibits aspiration).
Aspiration affects all three English voiceless plosives, [p t k].

Spanish [b d g] are voiced throughout. English [b d g] are only partially voiced, unless surrounded by voiced sounds.
Here is a schematic VOT diagram from Cruttenden, Gimson’s Pronunciation of English (7th ed., Hodder, 2008). (Click to enlarge.)So far, this is the information given in all textbooks of phonetics. But there’s more that can be said. We’ll return to the subject tomorrow.
If you want measurements of VOT in milliseconds, consult a textbook or measure a waveform. The usual value given for English VOT in words like pair is of the order of 40-75 ms.