By Aaron W. Rockwell, Staff Writer
From being on a journey to learning a new language, I often think about timetables of learning and how much time after I learn the language I will retain it. I often hear people talk about how they took a language for two to three years in high school, but currently can’t mutter a decent word in the language. I do not think this is solely a reflection on the education system doing a bad job of teaching second languages to high schoolers (though there probably is something to be said about how some students in the programs only go to check the box).
Thus, as my brain swirls with numbers, I wondered what percentage of a language is lost based on time. Is it a straight line rate of decay, such as X number of learned words lost per day/month? First off, the research on this topic is sparse due to the fact that it is difficult to measure. My search led to not being able to identify a single quantifiable story of lost heritage language, but I loosely recall somewhere hearing of someone at 6 years old losing their heritage language, and recently read this comment of a man losing his at 8 years old.
A child learns words at an exponential speed until hitting 42,000 words, which is about the average a 20-year-old will know. Here is what that would look like in table form, and then graphically.
| Age | Words Known |
| 12 months | 4 |
| 18 months | 50 |
| 24 months | 250 |
| 30 months | 450 |
| 36 months (3 years) | 1000 |
| 42 months | 1200 |
| 48 months (4 years) | 1600 |
| 54 months | 1900 |
| 60 months (5 years) | 2350 |
| 72 months (6 years) | 4800 |
| 144 months (12 years) | 42000 |
Data Courtesy: gwu.edu
You can thus conclude that a six-year-old knows approximately 4,800 words and an eight-year-old knows ~11,250 words. In the above-mentioned instance, the man claims to have lost over 10,000 words of his heritage language. I’m incredulous at that point; I think that at any point before 5 years old, it’s possible to lose a heritage language because of the lack of word knowledge and the number of thoughts in the language.
Here are some semi-random facts I discovered while looking up this topic, trying to tie in how many thoughts to words happen, but it did not pan out:
One last point on language acquisition: if the graph is true, then the peak number of words learned in a year for a child is 10,375. This is also around the number of words needed in a language to easily discover new words with context clues.