Why is "小小" pronounced as "xué xiǎo"? In the classic 相声《卖马》, near the beginning is a line that goes:


  在下王老好的便是，就在这潞州天堂县开了一个*小小*的店房


but in that line, "小小" was pronounced as "xué xiǎo". Here's a clip: http://youtu.be/cB391VthT4Q?t=1m11s

Why is this pronunciation used? Is it a specific dialect? And if so, what?


At first I thought perhaps it originated from Peking Opera, because the piece was adapted from the Peking Opera piece 《秦琼卖马》. However finding a clip online, the correct "xiao xiao" pronunciation was used: http://youtu.be/EUvd28rphTQ?t=2m48s
I don't think it was a mispronunciation, because there's a modern version by 郭德纲 of the same piece which also uses the "xué xiǎo" pronunciation: http://youtu.be/ixk1JoE3-Go?t=1m49s
This particular pronunciation is traditionally used in crosstalk, especially in the northern area of China. I think it's related to Tianjin dialect. Today Chinese only pronounce 小小 as 'xiaoxiao'.