I've changed the boot sequence of Knoppix 6.2 adding "lang=pl keyboard=pl xkeyboard=pl" and it looks fine, cause there are signs like "ą,ę,ć,ś,ż" in the STart menu.
The only problem is with typing those letters when I use the shortcuts like "Ctrl+a", "Ctrl+e" and so on which gives me "ą", "ę" ad that alike.
Every time when I hit the keyboard that way, some menu is being launched or some function inside any program I use for writing.
I can't find the docklet or mod inside Knoppix that would be responsible for it and I can't find any clue how could I set some keyboard and if so what keyboard type for my country - Poland ("QWERTY with ą,ę,ó,ś,ć,ż,ź,ń signs".

Mini Computer Vacuum USB Keyboard Cleaner PC Laptop Brush Dust Cleaning Kit NEW
$13.89
95000PA Wireless Car Vacuum Cleaner Air Blower Wireless Handheld Rechargeable US
$21.98
LEVOIT Cordless Vacuum Cleaner, Stick Vac with Tangle-Resistant Design, Up to...
$167.63
High-Power Cordless Air Duster 480,000 RPM - Rechargeable, Adjustable Speed, Tur
$127.99
Compressed Air Duster Rechargeable Computer Vacuum Cleaner for PC Keyboard Toys
$16.99
2-in-1 Compressed Air Duster & Vacuum, Brushless Motor, 320000RPM
$37.99
Powerffy Cordless Vacuum Cleaner N10 400W/30Kpa Power Nozzle Head Assembly.
$39.99
US Mini Computer Vacuum USB Keyboard Cleaner PC Laptop Brush Dust Cleaning Kits
$13.89
Compressed Air Duster 1 Button Adjustment 12000 RPM Air Blower Car Home Keyboard
$38.99
V3 Robot Vacuum and Mop Combo,Self-Charging,5000pa Strong Suction,WiFi/Alexa NIB
$82.00