So, according to Rioters, in various red posts that I'll attempt to compile...
The length of time you are in dishonorable really depends on two things: The punishment you got and also whether or not you are reforming:
https://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/unobngtr-how-player-behavior-penalties-affect-hextech-crafting?comment=000000000000
To add some clarity, more severe infractions incur longer ineligibility periods. If you’re currently ineligible for earned content, this is on you.
Regaining honor is dependent on your behavior. However, Rioters have given us an estimate:
https://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/iLcIFjP0-how-permanent-ban-works?comment=000e
3 months is the average amount of time it takes to get an account into a better status from a 14-day ban. It is not a fixed number. There is no magic 3 month check the decrements your status. It is entirely related to your behavior.
The simple answer is to just stop being a jerk, stop doing the stuff that got you banned, and you will never have anything to worry about.
Remember that false reports don't affect you. It's about whether or not you are actually being toxic.
https://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/unobngtr-how-player-behavior-penalties-affect-hextech-crafting?show=flat&comment=00000000000000010001000200000000000000000001
Actually, Erdrik is correct here.
A report flags a game for review. They do not establish guilt. The game is then reviewed for harassment, feeding, etc. This is why 'troll reporting' or 'gang reporting' do not work. False or inaccurate reports are thrown out.
You cannot ever be punished for saying nothing .. unless of course it's for something gameplay related like feeding, afking or cheating. But, you can never be punished for offensive language, hate speech or verbal abuse if you said nothing.
Now, as for your chats and how they affect you:
It is true that so long as you do not create a negative experience through chat, you will regain your honor.
https://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/unobngtr-how-player-behavior-penalties-affect-hextech-crafting?show=flat&comment=00120000
What you're doing is totally fine. Neutral or positive play is really all we're asking for.
"Me keeping quiet and playing the game as normal, is me being sportsmanlike." Just keep doing what you're doing, you don't need to be some paragon of good behavior to get loot. Just play games and don't create bad experiences for other people.
However, it has been said that your chats are graded on a spectrum of negative through neutral through positive.
https://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/PzY1ArN3-we-dont-ban-people-for-asking-for-reports?show=flat&comment=000400000000
Where the confusion creeps in is when you try to reduce things down to: Does "X" mean penalties. Instant Feedback only works that way with hate speech and threats of harm. That's the sort of harassment the team is much more focused on. Report calling is often a minor negative thing, but say there's a spectrum of chat where 1 is hyper-friendly, 5 is neutral, and 10 is literal death threats, this is like a 6.
So based on what is being tracked by Riot, I think that being positive will help you get out of dishonorable faster, however, a rioter (I can't find the post that has it atm) has said that the way to get out of dishonorable is not necessarily to be honorable, but to not be dishonorable. Boornes said something similar in an earlier quote above where he said they're only looking for neutral and positive play and that you don't have to be a paragon to gain honor loot.
EDIT: also, the IFS isn't just a trigger word system, it's a machine learning system
https://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/MIBGEN1J-the-issue-with-the-behaviour-system-is-that-it-is-too-black-and-white?comment=0005
Furthermore, you don't get punished for swearing. Fuck. Shit.
https://boards.na.leagueoflegends.com/en/c/player-behavior-moderation/iE97lQZW-make-reporting-system-more-efficient?comment=0000000000000000000100000000
The censored word list is in no way linked to the chat log evaluation engine. We let people censor out swearing, but we don't penalize for swearing if you aren't attacking other people or using hate speech.
You get punished for attacking people and being an asshole to others. Lots of people mistake bundled swears and flames, like "you're a fucking feeding noob piece of shit that needs to uninstall" you're getting punished for the flame, not because you said fuck and shit.
