Is this the language pack you tried to install?

http://ftp.mozilla.org/pub/thunderbird/releases/52.9.1/win32/xpi/nl.xpi

To install, drag the link and drop it onto Tools/Add-ons/Extensions in TB.

Thank you for your quick reaction. I succeeded to drop the link onto Tools/Add-ons/Extensions in TB, as demanded.

Result : the menu of the modules displays now - Catalogue - Extensions : unchanged and contains only "Lightning" - Appearance - Plugins - Languages : this containsnow "Nederlands Language Pack 52.9.1". See image in annex.

Trying to write an e-mail in dutch : on the right of spelling ("orthographe"), only French remains allowed. "Dutch" (Nederlands) does not appear in the choice. See image in annex.

Regards, Bernard Ameye 19-07-2018

The language pack only changes the language of the menus (if it's enabled). To include the ability to spell-check in Dutch, add the dictionary from this page:

https://addons.thunderbird.net/en-US/thunderbird/addon/woordenboek-nederlands/

Once again, drag the Download Now and drop it onto Tools/Add-ons/Extensions; there will now be a section 'Dictionaries' in Add-ons. To choose the default spell-checking dictionary, make the selection in Tools/Options/Composition/Spelling. Both the French and Dutch spell-checkers can be invoked when the interface language is either French or Dutch. Of course, if you only need the Dutch dictionary, you can Remove the Dutch language pack.

I proceeded once again as stated in your response above. This time, TB refused to install the downloaded complementary module (from your link) and displays a message in red, saying that the reason is that this module is corrupted. See image in annex.

When I drag the Download Now button for the Dutch dictionary and drop it onto Tools/Add-ons/Extensions, the window in the first attached picture appears, then clicking 'Install Now' completes the installation. The second attached picture shows the Dutch dictionary installed in TB.

Perhaps you have an antivirus program corrupting or interfering with the download of the dictionary xpi install file?

https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

TB refuses to install the downloaded complementary module. See previous sent image. The antivirus program is Norton 360 of the most recent version. See annex. What else can I do ?

Try this: right-click on the Download Now button, Save Link as..., and save the xpi installer file to your computer. Then open Tools/Add-ons/Extensions and click the icon next to the search box in the upper right corner, select Install Add-on from file... and select the xpi file. Either turn off Norton or tell it to allow the installation.

Your last procedure led to positive results: I saved the link into a file and asked to install the module from this file. I had to allow the installation by giving authorization by means of a button, somewhere in “advanced”. You can see the result on screen shots a and b. Thereafter I restarted Thunderbird. But a test of writing in Dutch remains negative: I still only have one orthograph verificator: see screen shot c. Your advice? Is it necessary to wait till the next version of Thunderbird or till the next “official” distribution of the Dutch language pack? The official version is still 52.0: see screen shot d. Kind regards.

You have managed to install the NL language pack, but as stated above, you must install the NL dictionary (woordenboek) to have the NL spellchecking option ('orthograph verificator') in the message composer.

Here is the link to the file that you can install the same way as you did for the language pack:

https://addons.thunderbird.net/thunderbird/downloads/latest/woordenboek-nederlands/addon-3291-latest.xpi?src=dp-btn-primary

Your message solved my question today ! See two screen shots in annex.

I am very satisfied ! Many thanks for your patient coaching!! BA

Now I have the same problem with the English package.

I proceeded as for the Dutch (see screen shots e and f) but at writing, the package seems not been installed. (see screen shot g).

Here is the link for the US English dictionary:

https://addons.thunderbird.net/thunderbird/downloads/latest/us-english-dictionary/addon-677644-latest.xpi?src=dp-btn-primary

Successful installation! See screen shots h and i annexed. I am delighted with all these positive results.

I hope Thunderbird will automatically pick up these language packages when editing later versions.

Kind regards, BA

BernardAmeye said

I hope Thunderbird will automatically pick up these language packages when editing later versions.

Note the Language Packs are for changing the language of the User Interface or UI of the menus and such.

Unless you want to have one install of say Thunderbird or Firefox but be able to change the UI to another language instead of have two or more installs.

The Dictionaries are what are used for the spell checker. Only a few locales comes with a dictionary due to license reasons.

There are a lot of bilingual or three lingual countries. So is mine and we are very inclined to express ourselves properly, in writing at least. I have been using Thunderbird under Windows XP during more than 10 years. I could take advantage of the spell checker or whatever, both in French and Dutch. This facility was transmitted to each successive version of Thunderbird, without any problem and without re-installation of the modules.

Recently I switched to Windows 10 and Thunderbird version 52.9.1. Thanks to Mozilla's recent support, I was able to upload and install the spell checker for both Dutch and English, my mother language being French and all the user interfaces being in French.

The only quoted wish is to be able to enjoy from now on the same flexibility with each new version of Thunderbird, without having to reinstall both language modules separately.

Moreover, Thunderbird offers a large choice of languages and let the user choose the dictionary or the language package of his choice (when available) without any restriction. See screen shots 1 and 2 in annex.

So, I did not yet understand the meaning of your comment.

BA 1-08-2018