[IgnareAcademy]

In Linux install the dictconv package. Be aware that it is still buggy, and not all dictionaries will be perfectly converted.

Then download a dictionary, extract it to a new folder, and in this folder open a console.
In this console type for example (to transform a stardict dictionary which contains three files ending with .ifo .idx and .dz; the goal is to get a new file ending with .index):
dictconv -o dictd_www.freedict.de_eng-deu.index dictd_www.freedict.de_eng-deu.ifo

It might take an hour for a dictionary of a few megabytes!
In the end you get these messages:
Results
File: dictd_www.freedict.de_eng-deu.index
Title: English - German
Author:
Email:
Version:
License:
Description: Made by Hu Zheng
Original Language:
Destination Language:
Headwords: 93101
Words: 93101

Then you get two new files (.index and .dict). You must transform the .dict file into a .dz file. To do so you need to install the dictzip package. Then type something like this in a console:
dictzip dictd_www.freedict.de_eng-deu.dict

Copy the .index file and the new .dz file to the dict folder you have created on the SD card you use in your Hanlin/Hanlin clone.

Then when you open an .rtf file with cr3 (long press of the key corresponding to the number of the file, then choose 2), you need to press OK and then 4 to use the dictionary.
Then for example if you want the translation of a word beginning with the letter a, b, c, d or e, just press 1 and then press the < or > keys (those on the left of the screen) to reach the word you wish to translate, then press OK. The definition may be longer than one screen, so do not hesitate to use the > key. Press OK again to exit the translation.

It would be perfect if it were possible to use more than one dictionary, or to be able to choose which dictionary to use.