Why does this store named サァラ have a small ァ in the name?


Over on [this awesome answer about old and unused katakana
forms](https://japanese.stackexchange.com/a/15120/119), I notice that among
the examples is the word "valve", written as `ヷァルブ`. It has a small `ァ`
character in addition to the `ヷ` that precedes it. What puzzles me is that I
can't imagine how `ヷァルブ` would be pronounced any differently than `ヷルブ`. Maybe
the small `ァ` does the same thing as `ー`, but then why not write it as `ヷールブ`?
Also, I'm no expert on katakanization of English, but I wouldn't think
extending the vowel sound in "valve" would be the right way to convert it.

`ヷァルブ` might be an archaic way of writing "valve" that is no longer in use,
but it reminded me of a store I pass by on my bike now and again, called
[`サァラ麻布{あざぶ}`](http://www.sala-azabu.co.jp/). I've never been interested in
the furniture they sell, but the name has always caught my attention. They
write the English version of their name as "[Sala Azabu](http://www.sala-
azabu.co.jp/index_e.html)". If I had seen the English first and someone asked
me to write it in katakana, I'd have simply gone with `サラ`.

What is the small `ァ` character doing in these instances? How is `サァ`
pronounced differently from `サー` or `サ`?




### On the pronunciation

サ has a length of 1 mora, サァ and サー are both 2 mora.

> 前の音があ段の音の場合は、長音と同じように扱う。 If an A-row sound precedes it, ァ is treated just
> like ー.

### On the usage

Usually used in foreign words.

> 主に外来語や方言において使用される。 Mainly used in foreign or dialectal words.

### Source

<http://ja.wikipedia.org/wiki/%E3%81%81>

See also <http://ja.wikipedia.org/wiki/%E5%B0%8F%E6%9B%B8%E3%81%8D>

