san·dhi 
(sŭndē, săn-)
(sŭndē, săn-)n.
Modification of the sound of a word or morpheme when juxtaposed with another, especially in fluent speech, as the modification of the pronunciation of don't in don't you from its pronunciation in isolation or in a phrase like don't we.
[Sanskrit saṃdhiḥ, union, sandhi : sam, together; see sem-1 in the Appendix of Indo-European roots + dadhāti, dhī-, he places; see dhē- in the Appendix of Indo-European roots.]