The word is sabroso and am wondering which is the correct diminutive form?
- Sabrocita, or
I've seen both used in writings, names of restaurants, etc. Is there a rule?
"-cito" is a very common diminutive ending; however, the general rule is that words that end in '-o' usually lose the '-o', to have it replaced with '-ito'. Similarly, the diminutive of words that end in '-a' is usually '-ita'. Plurals that end in '-os' and '-as' are changed to '-itos' and '-itas', respectively. So, for example, vaso → vasito, tacos → taquitos, pluma → plumita.
There are exceptions to this rule, however, such as 'sofá' → 'sofacito', 'manos' → 'manitas'.
Since one can find many instances of the diminutive written with c and there is nothing about it published by the RAE, I used ngram as a source of empirical evidence; this is what I found: "sabrosito" is used a lot and "sabrocito" is rarely used. It's safe to assume that the latter is not right.
Searching for an official source I found this interesting article published by fundeu which mentions these rules:
Es verdad que una de las formas de construir los diminutivos es agregar el sufijo -cito, con c, como en avioncito, noviecito y Carmencita, pero si la palabra original termina en s, se mantiene la s y se agrega -ito, como en Andresito y Luisitos.
As stated in the same article, this does not apply to plurals:
En este caso se debe partir del sustantivo singular mamá, cuyo diminutivo es mamacita, y ahí sí agregar la -s para formar los plurales, mamás y mamacitas.
Given this it is easy to see why words ended in "so" will form the diminutive this way. It would not make sense to remove the '-o' and add '-cito'.
If the last syllable of the word includes the letter s, the diminutive is formed by adding -ito to the end of the word and preserving the s:
Otherwise the diminutives are formed by adding -cito/a to the end of the word:
This is explained in ¿Cafesito o cafecito? La ortografía de los diminutivos:
Si la palabra de origen tiene ese en la última sílaba, la conserva en la terminación -ito, -ita; si no lleva ese debe usarse -cito, -cita. En los casos en que el primitivo lleva zeta ésta se convierte en ce.
If the original word has S in the last syllable, it keeps it in the endings -ito/a; if it does not have S, -cito/a must be used. In the cases where the original has Z, this becomes C.
So you have:
It is also interesting to read Reglas ortográficas para formar diminutivos regulares e irregulares. There we read about the basics of this topic:
Los diminutivos son sufijos o morfemas que no cuentan con un significado propio, pero que al agregarse a la raíz —o sea, a la palabra— logran que ésta se transforme en otra.
And makes us see the underlying idea: sabroso is the word and sabros the root to which we add the suffix. So the s at the end does not change no matter what suffix we add to it. We can say sabroso, sabrosón, sabrosísimo or whatever, all of them having the common stem sabros, not sabroc.
This is kind of errors come often from Hispanic America, where s and c are pronounced the same way /s/. In Spain we do distinguish these sounds, so the word sabrocito would not sound fine; however, in those countries both sabrosito and sabrocito have the same sound /sabrosito/.
As others have shown, the version with the S is the correct one. I will offer a conjecture as to why the version with C is also common.
First reason: Large swaths of Spanish speakers, at least in Mexico, the Spanish-speaking country I know well, have rather vague ideas about correct spelling. I think this is at least partly because when you are working with a language whose spelling is so straightforward for the most part, you can get away with just sounding things out and not having to bother learning correct spelling.
Second reason: there are lots of common words whose correct spelling ends with '-cito' and '-cita'. So people get in the habit of spelling the ending sound with a C, without stopping to think about which one would be logically correct, based on the original word.