What are hard/soft vowels/consonants?

Answer 1

What language? I know them in Spanish, but not English--do they exist in English? I'd like to know, too...

Edit 11/18: Actually, I have seen reference to hard and soft quite a bit, even along side other linguistic terminology so I think it is not useless. However, it seems more common in other languages. Lots of references to it in Russian language. Also in Bulgarian and Dutch. The only example of hard vs. soft consonant I can think of in English is C which can either be pronounced like "s" (soft) or "k" (hard).

I also found the following:
From: Concise Oxford Companion to the English Language | Date: 1998 | Author: TOM McARTHUR
HARD AND SOFT. (1) Qualities of the letters C and G that depend on whether they are pronounced like k or s in the case of c or like the g in get or the j in jet in the case of g. When hard, c and g are pronounced as velar stops, as in cap/gap; when soft, c is pronounced as a sibilant, g as an affricate, as in cell/gell. (2) In phonetics, in the description of consonants, hard is an older term for fortis (articulated with considerable muscular tension or force of breath or plosion, as with the voiceless consonants of English, such as /p, t, k, s/) and soft for lenis (articulated with little tension, as with the voiced consonants, such as /b, d, g, z/).

Answer 2

These are words that people use to talk about sounds when they don't know technical language for describing sounds. These terms are basically useless.