Differences and Similarities between Consonants

B and V

No complications with these two consonants. They are pronounced different in Spain /b/ and /v/, and the same sound in Latin America /b/.

 C and Z

People in Spain pronounce "ce"- "ci" and Z (with any vowel) like /θ/. In Latin America make this sound like /s/

C- K and Q

"C" ⟨c⟩ represents the "soft" value before ⟨e⟩ or ⟨i⟩ and a "hard" value of /k/ elsewhere.

"K" /k/ is the easiest letter here, because there is not different sound depending of the vowel. They are the same than ca, que, qui, co, cu.

In Spanish, "Q" ‹qu› represents /k/ or /kw/; ‹qu› replaces ‹c› for /k/ before front vowels ‹i› and ‹e›, since in Spanish 'c' represents a fricative or affricate before front vowels. There are not spanish words  with "q" combinated with "a", "o" nor "u".

 

G and J

"G" sounds like "J" when is before front vowels "e" and "i". Needs a "u" before "e" and  "i" to have the sound  /g/ like "give" in English. When "u" is "ü" its sounds is a diphthong, no one.
"J" always has the same sound.

H 

No sound for this consonant. If it's before a vowel then that's the sound, like "א-ע" in Hebrew. If it's between C and a vowel then its sound is /t∫/ (ch).

Ñ

This is the written form of the same sound we can find in Italian when we see written "gn".

Y and LL

Both have the same sound when are followed by a vowel /ʝ/. In spelling have different use.

NOTE: People in Argentina and Uruguay pronounce "LL" and "Y" as /ʃ/

R- RR

Ok! to make it pretty easy: the sound is /r/ like a tiger when this letter is:

(1)        at the beginning of a word (R)

(2)        after a vowel

(3)        between a consonant and a vowel

(4)        or between TWO (2) vowels (RR).

And its sound is /ɾ/ a softer sound than the last one when it is between TWO VOWELS (R).

 S- X and Z

In Latin America all these consonants have the same sound when are followed by a vowel /s/