Hi.  On TV you may not hear the sounds, the tongue-play within the chamber of the mouth and the tiny air stops, etcetera that occur when people speak.  You need to be face-to-face with your pronunciation coach.

I can well see how you "hear" FAX for facts, because the sounds are about identical in those two words.  You know from the context when someone tells you to send them a FAX that they are not talking about the "facts."  That is the context or the syntax of the language.

GIFTS is spelled that way, but, actually when you pronounce it, you DO HEAR "GIFS."  The ortography of words is a clue to their meaning, so the spelling is important when you are reading.

ASKED.  Pronounce ASK.  Feel and hear the little "kick" when you produce the "k."  Now, add the past tense syllable, "ed."  In this particular word, "ed" is pronounced as if it were a "t."  Your mouth cannot go from the "K" to the "T" without trouble, so the "K" gets forgiven, softened, blurred in pronunciation..it just about disappears totally so that your tongue is able to touch the alveolar ridge just behind your front teeth.  That is the positioning of the tongue within the mouth that causes this particular phenomenon.  KICKed...see above for "asked."  These kinds of sound changes are required due to the placement of the tongue.

On that subject, I might point your interest to the pronunciation of "a" or "an."  Before a consonant you use "a" and before a vowel you use "an."
Try it.  A dog.  A cat.  A shoe.  A house.  Now consonants.....An elephant, An egg, An old man, An idiot.  If you were to reverse this speaking pattern, you'd quickly feel the ugliness and difficulty forced into your tongue movements.

An dog; an cat, an shoe; an house..a elephant; a egg; a old man; a idiot.
Carole in Umatilla, OR