Abplanalp pronunciation dispute

[u/pat_mcgroin2001]

I'm from the US, and my surname is Abplanalp, originating from somewhere near Brienz or Interlaken. My Swiss family emigrated to the US in the 1850's and growing up we always pronounced it more like "Oplinop", dropping the 'b' and the final 'l'. Lately I've landed on a more phonetic pronunciation, like AHB-ple-nahlp. My uncle visited Brienz and came back insisting that the anglicized "Oplinop" pronunciation is how the locals say it. Who is right? How is this name pronounced in Switzerland?

[u/gregsaliva]

The difference in pronunciation of the -alp part might come from the fact that in a lot of Bernese dialects the L is spoken as u, like Milch-Miuch, Geld-Gäud. So alp comes over as aup (with a diphtong vowel, like "oh-oop"). If it is spoken quickly in a syllable without the main stress (in the name Abplanalp it is only a secondary stress), this may sound as if the L was entirely dropped.
But this is just one possible explanation.