As solution, I recommend you boot from live CD and change password of your partition to latin layout.
Access an encrypted system from a Live CD:
In the case of emergency, it may be useful to have access to the encrypted files of a system installed by using this manual (you need the password, for sure). Boot the Live CD and install the needed software:
sudo apt-get install lvm2 cryptsetup
sudo modprobe dm-crypt
Open/decrypt the device (replace sda2 with your device if needed):
sudo cryptsetup luksOpen /dev/sda2 lvm
Activate the LVM to get /dev/ubuntu/home, /dev/ubuntu/root and /dev/ubuntu/swap:
sudo pvscan
sudo vgscan
sudo lvscan
sudo vgchange -a y
Mount the root and home partition:
sudo mkdir /mnt/root
sudo mount /dev/ubuntu/root /mnt/root
sudo mkdir /mnt/home
sudo mount /dev/ubuntu/home /mnt/home
Now you can access your home partition via /mnt/home, the root partition is located at /mnt/root. So you can copy or edit all of your data. If you don't have enough permissions to copy needed files, try it with a filemanager started with gksudo nautilus.
Change/add/remove passwords:
LUKS is able to manage up to eight passwords at the same time. Each password will be stored in a so-called slot (0-7). The currently used slots of the encrypted partition can be printed out by using luksDump (don't forget to replace sdX2 with your own partition, e.g. sda2):
sudo cryptsetup luksDump /dev/sdX2
[...example output follows...]
Key Slot 0: ENABLED
Iterations: xxxxxx
Salt: [...]
[...]
Key material offset: 8
AF stripes: 4000
Key Slot 1: DISABLED
Key Slot 2: DISABLED
Key Slot 3: DISABLED
Key Slot 4: DISABLED
Key Slot 5: DISABLED
Key Slot 6: DISABLED
Key Slot 7: DISABLED
To add a new password, use luksAddKey:
sudo cryptsetup luksAddKey /dev/sdX2
To remove an existing password, use luksRemoveKey:
sudo cryptsetup luksRemoveKey /dev/sdX2
Source: http://blog.andreas-haerter.com/2011/06/18/ubuntu-full-disk-encryption-lvm-luks#tips_and_tricks
Some solutions to change password encrypted LVM: https://askubuntu.com/a/110195/881020