Joshua Bousquette. "From Bidialectal to Bilingual: Evidence for multi-stage language shift in Lester W. J. ‘Smoky’ Seifert’s 1946-1949 Wisconsin German Recordings." American Speech, A Quarterly of Linguistic Usage (June 2020): 1-30. Duke University Press. The present work examines nominal case marking in Wisconsin Heritage German, based on audio recordings of six speakers made in the late 1940s. Linguistic data provide positive evidence for a four-case nominal system characteristic of Standard German. At the same time, biographical and demographic information show that the heritage varieties acquired and spoken in the home often employed a different nominal system, which often exhibited dative-accusative case syncretism and lacked genitive case – and these features surface even when speaking Standard German. These data strongly suggest that speakers were proficient in both their heritage variety of German acquired through naturalistic means, as well as in Standard German, acquired through institutional support in educational and religious domains. Over time, these formal German-language domains shifted to externally-oriented, English-language institutions. Standard German was no longer supported, while the heritage variety was retained in domestic and social domains. Subsequent case syncretism in Wisconsin Heritage German therefore reflects the retention of pre-immigration, non-standard varieties, rather than a morphological change in the heritage grammar. This work concludes by proposing a multi-stage model of domain-specific language shift, informed by both synchronic variation within the community, as well as by social factors affecting language shift over time.