Why Spaniards do not speak with a "lisp"

Say the word thin. Ok. Now say the word sin. Did you pronounce them differently? Does the fact that you pronounce them differently mean that you have a lisp? No, what it means is that you have that first phoneme of the word thin in your dialect of English.

Now pronounce the word sima like this: "seema." That is "cavidad o grieta grande y muy profunda en la tierra." [A big deep hole in the ground].

Now pronounce the word cima like this: "theema." [use the unvoiced sound of th as in thin, not the voiced sound of that. A cima is "parte más alta de un terreno elevado." In other words, a peak, not a hole in the ground.

Latin Americans pronounce these two words with opposite meanings in the same way, because they do not have a phonetic distinction between s and c/z.

The Spanish of Spain (outside Andalusia) distinguishes between sima and cima, the way English distinguishes between thin and sin. My dialect of English does not distinguish between cot and caught, but I would not say that someone who pronounced the words differently had a speech impediment like a "lisp." It is pretty stupid to call a sound made by millions of people speaking their own language, evidence of a "lisp." Not that there's anything wrong with a lisp. What is wrong is stupid people using this word for this. By this logic almost all speakers of English have lisp too, if they don't pronounce thin as sin.

In Andalusia, there is seseo. That is the merger of two sounds. In Spanish American too.

In parts of Andalusia, the distinction is lost in the other direction with the ceceo. So all sibilants become the th. Again, this is simply a phonetic reality of the dialect and has nothing to do with a so-called lisp.