Writing is much more preferable to speaking, especially when English is concerned. Let’s just take vowels for example. I can’t distinguish between “pet”,”port”, “pot”, “pat”, “part”. They all sound the same to me. This means whether you are telling me you own a cat, a harbor, a cooking utensil, or a role in a TV show, I can’t tell the difference. Also I am too embarrassed to ask people to repeat. Repeat is either an admission that my ears can’t do their job, or just a waste of time since I hear no difference the second time around.
“Sink” and “think” sound the same to me too. I wouldn’t be able to know, just by listening, whether somebody is wracking his mind on a midlife existential crisis, or plunging into the bottom of something, like a lake for example.
In defense of my ears, I declare that the five different vowels create such a small difference in air vibrations that they are mutually indistinguishable. It’s a useless declaration. I know. Better just admit that my ears are not picking up certain sounds, like having the blind spots in the eyes. A lot of things escape our senses, and learning English just make us more aware of our own imperfections. Worse, I know this imperfections will stay that way. The ears seem impervious to learning and stubbornly refuse to improve. No matter how often you tell your ears that there should be a difference there, your ears just don’t listen.
Fortunately, there’s something called “context”, which rescues people from language mishaps. The word “think” and “sink” are almost always used in different contexts. The same thing happens to “pet”,”port”, “pot”, “pat”, “part”. One cannot possibly mishear a sinking ship since there’s no such thing as a thinking ship–with the advancement of AI right now, who knows. That might happen.
The difference, be it big or small, is rather in the eyes and ears of the beholder. In one language and culture, the difference seems to be night and day; in another language and culture, the same difference is invisible or inaudible.