Depending on the point of view, changes can have small or large consequences on a system. Regarding human language, we see this kind of relativism in a claim made by linguist David Lightfoot: language change can be considered abrupt if we focus on its internal properties or gradual if we focus on external ones. Two well documented cases of language changes, usually described as transitions from null to overt pronominal subjects in Old French and in modern Brazilian Portuguese, are used as

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... cal analyses for our evaluation of Lightfoot's claim.