Why is it
обо мне
обо всём
but
передо мной
перед всем
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Sign up to join this communityПередо — предлог, употребляется перед формами мной, мною, а также перед формами творительного падежа существительных, в которых представлены начальные сочетания «ль, л, м, р + согласная».
So передо is used instead of перед before nouns in instrumental case which start with “ль, л, м, р + consonant”.
The rules for о/об/обо are different.
I think it is incorrect to compare two different prepositions which require different cases.
In general, -о is added when it's hard to pronounce the consonant cluster.
I'm not sure if some particular rule applies here, but I think that vowel о
is inserted before two consecutive sonorants (лнмр
) in next word so it's easier to pronounce, мн
is the most frequent one.
That I'm talking about is that перед мной
is pretty legitimate form (esp. in form пред мной
for example), however о
is usually added for ease of prononciation. While there is no need to insert о
in обо
since it's already there.
об
changes to обо
... I'm asking why об
does change, but перед
does NOT change when used with всё
, yet both change when used with я
.
Aug 17, 2012 at 8:11
обо
is об
+ о
, just as передо
is перед
+ о
. The two should follow the same rule, that о
is added before consonant clusters.
Aug 17, 2012 at 10:15
об
is o
+ б
, while обо
is о
+ б
+ о
and is synonym to о
. Thus обо мне
is actully equv. to о мне
. Об
is used insted of о
if next word is starts from vowel, e.g. об этом
.
Aug 17, 2012 at 10:20
передо
IS перед
+ о
, the same way as об
is о
+ б
+ о
Aug 17, 2012 at 13:02
-o
ending.в
andс
inвсем
and this is the reason for 'перед всем' to be acceptable. However, I'm not devoted enough to dig into the matter.