Now, let me ask you a few questions.
Even in Japanese, there are different ways to read it. As written in the how-to, they should probably be avoided.
However, if it's part of a word, it would be an exception, I think. For example,
- 一緒 meaning "together"
- 十分 meaning "enough"
- 三十路 meaning "thirty years old"
- 五十嵐 is a person's family name
- 九十九髪 meaning "old woman's gray hair" or "old woman with gray hair"
2. っ/ッ at the end of a word
Some of the words are indeed as exclamations. For example, "あっ" and "えっ".
There is no specific pronunciation for this spelling. The pronunciation depends on the speaker.
It is written to express some "momentum". In other words, a stress.
Can I include it in a sentence?
3. Sentence length
How about 35 characters or less, excluding punctuation?
In reference to the topic on sentence length limit, sentences that can be spoken in less than 10 seconds seem to be appropriate.
This is the reference time that the native speaker read slowly:
- 今日は良い天気ですね。(3 seconds / 10 characters)
- 私はそれを恋だなんて思ってないけどね。(5 seconds / 18 characters)
- お父さんは箔が付くからって言うけど、あたしとしちゃどうだって良いね。(7 seconds / 32 characters)
- このサハラというのが本名から取ったにしろ、サハラ砂漠か何かから取ったにしろ、大して興味は無い。(11 seconds / 44 characters)
4. Range of kanji to be used
This is a difficult question. Can I write in the sense of a native speaker?
For example, the kanji for 俺 (meaning "I") is a very popular first person character, and even children can read it, but I was surprised to see that someone read it as kare (meaning "he") in Common Voice.
It is not wrong to write it in hiragana. However, a sentence with many hiragana characters becomes difficult to read.
I am automatically translating it into English. Sorry if that was unnatural!
I hope to inspire you.