A linguist analyzing historical texts observes that a grammatical construction appears once every 2,500 words in a 19th-century corpus. In a modern corpus of 150,000 words, it appears 90 times. How many times more frequent is it in the modern corpus compared to the historical average?

["Title: Unearthing Language Evolution: How a 19th-Century Grammatical Construction Compares to Modern Usage", "Linguists studying historical language patterns often uncover fascinating shifts in grammar, vocabulary, and usage over time. A recent analysis of a 19th-century corpus reveals a notable grammatical construction occurring once every 2,500 words. But how does this compare to its frequency in a modern corpus—specifically, a collection of 150,000 words, where the same construction appears 90 times?", "By calculating the relative frequency, we can determine just how much more prevalent this construction has become in contemporary language.", "### Historical Frequency: One Occurrence per 2,500 Words\nThe historical average comes from a 19th-century text dataset where the construction appears once every 2,500 words. In a hypothetical modern sample of 150,000 words, applying this rate predicts:", "[\n\frac{150,!000}{2,!500} = 60 \ ext{ occurrences}\n]", "Thus, the construction appears 60 times in the modern corpus under historical frequency assumptions.", "### Modern Observed Frequency: 90 Occurrences\nHowever, actual data shows 90 occurrences in the same 150,000-word modern text. This deviation points to a significant shift in usage.", "### Frequency Ratio: Modern vs. Historical\nTo find how many times more frequent the construction is in the modern corpus, divide the modern count by the historical expectation:", "[\n\frac{90}{60} = 1.5\n]", "This means the grammatical construction appears 1.5 times more frequently in the modern corpus than in the 19th-century average. In other words, it is 50% more common today.", "### Implications for Language Change\nThis quantitative comparison highlights a measurable trend in language evolution. The steady rise in usage—evident from just 60 expected instances to 90 observed—suggests either greater expressive needs, rhythm shifts, or stylistic preferences in contemporary writing. Linguists use such data to map not just frequency, but underlying sociocultural and linguistic transformations.", "In summary, the grammatical construction’s increased rate by a factor of 1.5 offers compelling evidence of language dynamism across two centuries, underscoring how even subtle constructions reflect broader evolutionary patterns in communication.", "---", "This analysis demonstrates the power of corpus linguistics in revealing language change quantitatively—and how a simple ratio can illuminate deep structural shifts over time. For researchers and language enthusiasts, such comparisons enrich our understanding of how grammar adapts and endures."]