I'm Thai and living in Bangkok, so I'll answer specifically for Thai language.
How important are correct tones to understanding a whole sentence
(words in context) in tonal language?
If I use mostly right tones, but use few wrong tones, will be native
speaker able to decode and fill the right tones?
Or even few wrong tones will make the sentence ...
Learn Thai with Mod (Web site, YouTube channel) seems to be a direct equivalent.
Note, these are casual, unstructured lessons. It may or may not appear useful, depending on the learner's approach of language learning.
I speak both Mandarin and Cantonese, and I can tell you tones are pretty important, because it is like singing, if you sing on the wrong tone, sometimes we might be able to guess what you sing, but it won't be beautiful, and it might be misleading. Also it depends on how many words are off tone.
When my Cantonese was not good enough, one of my friends had ...
My go-to analogy for this is:
How important are final consonants in languages that have consonant clusters?
I'll refrain from giving an "eye-dialect" rendition, but it is true that, depending on exposure, English speakers do understand "a lot" when the interlocutor drops most of their final consonants. However, how much is "a lot"? More importantly, is it ...
I find it is often easier to read familiar texts or watch familiar videos translated into your target language. If you can read Harry Potter or watch the Simpsons in Thai, for instance, you will find the language more comprehensible than what you find in original Thai works.
I lived in Taiwan for two years speaking Mandarin Chinese (as a missionary for my church, but that is another story). Sometimes, I would speak funny to children on purpose to see if they could understand me. For example, I remember saying, "Ru4guo4 wo4 yi4zhi4 yong4 di4 si4 sheng4 gen4 ni4 jiang4, ni4 hui4 ting4 de4 dong4 ma4?". Which should be, "Ru2guo3 wo3 ...
500 is a very low number when comparing with the CEFR scheme. That puts you in the A1 category (out of 6: A1, A2, B1, B2, C1, C2). It may be that you know more vocabulary, but if you do not then it should be difficult to read most books.
That said, I think reading is the key to increasing vocabulary. With Thai, there is formal and informal language, ...
Tones are essential to the meaning of a tonal language. Two words that sound the same to a non-tonal language have a completely different meaning.
For example in Vietnamese, ma, má, mâ, and mà among others all have completely different meanings. That is why the language is called tonal because the tone of the word changes its meaning.
A similar analogy ...