Użyj XQuery:
declare @xml xml =
'<email>
<account language="en" />
</email>'
select @xml.value('(/email/account/@language)[1]', 'nvarchar(max)')
declare @t table (m xml)
insert @t values
('<email><account language="en" /></email>'),
('<email><account language="fr" /></email>')
select m.value('(/email/account/@language)[1]', 'nvarchar(max)')
from @t
Wyjście:
en
fr