For example, they have less honey that comes from the bears than honey that comes from the shop? I would say the same, יש להם פחות דבש מהדובים. If I felt that this sentence was ambiguous, I would say יש להם פחות דבש מאשר לדובים or יש להם פחות דבש ממה שיש לדובים to make it definitely "less than the bears". But... for some reason I don't feel that it's ambiguous. :-)
You're right, it's the same preposition - מ is from, but פחות מ/יותר מ means less / more than. I think some Hebrew-speaking English learners can be heard to say "less from" at first. It's just that a sentence like "they have less something from someone or somewhere" needs some context to make sense. Thinking of a way to demonstrate it: "this pizza is not so much from the oven, it's more from the microwave". הפיצה הזאת היא פחות מהתנור ויותר מהמיקרוגל.
Well, the word דֹּב is formed from a root דבב "to move gently, to walk softly". The word for bear was originally formed -דֻבּ DUBB- with endings, so that you could hear a [b]. In the plural this form continues. But as the singular lost its case edings, the double BB was reduced to a single B, which meant phonologically a [v], but the vowel was lowered (and originally lenghtened) as a compensation from [u] to [o], producing the new singular דֹּב.
Thank you, but Could you plz give me some few examples with another word?/for exemplo: We have the word עכביש where in it's plural form I've heard עכבישים(Ackvishim) so , the caf turned into ckaf, is there a sense for this? When it usually happens? Can I keep speaking "akavishim, Dovim", or do I have to changes my mind about it?
Well, I think in English people would understand "childs and "mouses" as well, but would recognise that you made an error. The reason, עַכָּבִישׁ changes in the plural is, that the syllable [ka] is no longer pretonic, but shifted one syllable more away from the stressed syllable. In this case Hebrew has a tendency to shorten it. Sometimes there even happens a resyllabification, so that a syllable is lost, like in עִפָּרוֹן [iparon] pencil, which has the plural עֶפְרוֹנִים [efronim], with the same change of the plosive [p] to the fricative [f].