Sim has basically hit the nail on the head. I started to learn Taiwanese when i lived there in 1997-8 but each time i went back and tried to speak to people I found that many people my age couldn't speak it. In Amoy it was the same, I was there last year and I did not here one child that could speak Hokkien. I heard a fair few in Penang though.
No-one ever tells me "you should speak Mandarin" when I speak to them in Hokkien, and I think it is because they have a better opinion of their own language than, say the people in Singapore or Amoy.
I may've told this story here before, but not lately.
Back in 2003, I "knew" a lot of Hoklo, but I wasn't used to expressing myself in Hoklo at speed, and I couldn't catch a lot of what people said, at least not on the fly. In TW everybody just switched to Mandarin on me. One person told me it was painful listening to me speak Hoklo. Someone else told me, "U don't speak Hoklo at all." U have to realize that in the TWese context, telling someone their Hoklo sucks can almost be a compliment, or rather a good-natured jab. Yet other people almost seemed to get angry that I would waste their time trying to speak Hoklo. And most of the people I knew well just didn't speak Hoklo in public on a daily basis. A taxi driver in Kelâng -- he looked Javanese but spoke Mandarin and Hoklo -- hinted that maybe I was hanging out with the wrong people, and he was probably right.
Then I went on a trip to Bangkok, Phi Phi, and Penang. On the bus from the Thai border to Georgetown, I
heard the driver and a passenger speaking this strange but strangely familiar language that had bits and pieces of Hoklo in it -- and what I would now (but not then) call a Teochew aura. Now I knew beforehand that half of Penang spoke Hokkien. I asked the passenger if they were speaking Hokkien. He gave me a weird look and said yeah. I spent two days on Penang. I saw people of all ages talking to each other in Hokkien. A 12-year-old kid working in a store walked up to me and asked, "Lú choē hámi̍h?", in Hokkien. A busload of 6-year-olds came up to the top of the Komtar Tower -- and they were all speaking Hokkien. Somebody asked me for directions in Cantonese, and they weren't at all surprised when I replied ... in Hokkien!
I took the bus around town... I went in a shop and they told me about the Snake Temple... I wasn't sure how to get to Ke̍klo̍ksī, so I stopped to ask these guys about my age -- in English -- and they switched to Hokkien on me. Actually they asked me, "Do U speak Chinese?" And I said, "Hokkiàn'oē?" And right away their eyes lit up and one guy started giving directions in Hokkien.
What I took away from Penang was a feeling that it was okay to speak Hoklo as non-native, with an accent, with mistakes... Communication is communication. And that confidence allowed me to improve quickly, so that when I got back to Tâipak, I went right back to imposing my Hoklo on people.
Soon after, my one friend that didn't mind speaking Hoklo with me (back then) said, "U know something, U are really speaking Hoklo now."
And strangely enough on the same trip I also ran into a street vendor in Yaowarat (Bangkok) who spoke Hoklo. I just pointed at something and said, "Ce ài goācē?", expecting a reply in Teochew, but she actually said Pehca̍p kho͘ or Poehca̍p kho͘ in straight-up Hokkien.
I haven't been back to Penang, but I was in Phuket a few yrs later. It totally reminded me of Penang: the faces, buildings, streets, hills, and beaches. And almost everyone I asked told me their father or mother or grandparents spoke some Hokkien. (But I wasn't asking the Malays and obviously Tai-looking people.)