Typology, Documentation, Description, and Typology Marianne Mithun University of California, Santa Barbara Abstract If the goals of linguistic typology, are, as described by Plank (2016): (a) to chart linguistic diversity (b) to seek out order or even unity in diversity knowledge of the current state of the art is an invaluable tool for almost any linguistic endeavor. For language documentation and description, knowing what distinctions, categories, and patterns have been observed in other languages makes it possible to identify them more quickly and thoroughly in an unfamiliar language. Knowing how they differ in detail can prompt us to tune into those details. Knowing what is rare cross-linguistically can ensure that unusual features are richly documented and prominent in descriptions. But if documentation and description are limited to filling in typological checklists, not only will much of the essence of each language be missed, but the field of typology will also suffer, as new variables and correlations will fail to surface, and our understanding of deeper factors behind cross-linguistic similarities and differences will not progress. 1. Typological awareness as a tool Looking at the work of early scholars such as Franz Boas and Edward Sapir, it is impossible not to be amazed at the richness of their documentation and the insight of their descriptions of languages so unlike the more familiar languages of Europe. It is unlikely that Boas first arrived on Baffin Island forewarned to watch for velar/uvular distinctions and ergativity. Now more than a century later, an awareness of what distinctions can be significant in languages and what kinds of systems recur can provide tremendous advantages, allowing us to spot potentially important features sooner and identify patterns on the basis of fewer examples. As typological findings become finer-grained, they serve as ever sharper tools for observation and analysis. It is now well known, for example, that languages are not simply nominative/accusative, ergative/absolutive, or agent/patient; different areas of grammar often show different patterns. Where there are differences, we know where to start looking for sub- patterns: pronominal systems are more likely to show nominative/accusative or agent/patient patterning, even if lexical noun phrases show ergative/absolutive patterning, but not the reverse, for example. We know, furthermore, that differential argument marking is not uncommon across languages. Rather than standing by helplessly when our ergative/absolutive patterns seem to founder, we can jump right into searching for principles behind the apparent exceptions. Perhaps only animate or identifiable (definite) expressions can carry absolutive marking, or can even have absolutive status at all.