The atmosphere around Lord Alberdine’s table is friendly. In fact, you catch the punch line of an anecdote he’s telling; it loses something without context but his guards enjoy it and burst into laughter, one even slams his fist into the table several times to make himself stop laughing. After the moment, Lord Alberdine finishes off his mug of ale and looks up at Sleth and says,

“Is there something I can do for you?”, his voice curious and lacks any trace of being posh or snobbish, as is common with nobility.

Lord Alberdine is a fairly young man of handsome features and a moderate build. His general demeanor and voice contrasts with his dress and even his station, this isn't the sort of place one would be "slumming it" as the saying goes. It appears he has more humble roots than your information suggests.