This paper presents a case study based on the writing of James Horner, one of the many Irish emigrants who crossed the Atlantic between the late 1700s and early 1800s. Communication between Horner and his family back in Ireland was kept through personal correspondence. His letters, which contain about 14,000 words in total, are part of the Corpus of Irish English Correspondence (CORIECOR), and they provide detailed accounts of his experiences and impressions of the recently adopted country. They also show progressive standardisation, which makes them an interesting site for historical sociolinguistic analysis: shifting from vernacular Irish English towards a more standardised type of English to some degree. Our study focuses on the use of subject-verb agreement and addresses the following research questions: does geographical and social mobility condition Horner's speech? If so, how does an individual's social status affect language? The findings reported below show that social mobility as well as dialect contact seem to have contributed to general standardisation and the subsequent blurring of identity markers in language use. The paper, thus, offers new perspectives on the analysis of intra-speaker variation using historical data and contributes to the discussion of the need for this type of micro-analysis in the area of historical sociolinguistics.
