docs: add some more explanations, do some reorganization of steps

docs/contributing.md

@@ -10,12 +10,16 @@ old version. Before registering new issue, test that issue can be reproduced wit
 [eSpeak NG online](https://odo.lv/Espeak) site.
 
 <a class="anchor" id="simlestep2">2. Review known [eSpeak NG issues](https://github.com/espeak-ng/espeak-ng/issues), particularly about
-[languages](https://github.com/espeak-ng/espeak-ng/labels/languages%2Fpronunciation) and add your comments 
-on existing issues. If necessary add new issue as described [here](https://help.github.com/en/articles/creating-an-issue).
+[languages](https://github.com/espeak-ng/espeak-ng/labels/languages%2Fpronunciation) and add your comments on existing issues.
 
 <a class="anchor" id="simlestep3">3. Look at and subscribe to [eSpeakNG mailing list](https://groups.io/g/espeak-ng)
 to view and discuss other related topics.
 
+<a class="anchor" id="simlestep4">4. If you decide to create new issue, look at guide [here](https://help.github.com/en/articles/creating-an-issue) and provide following information:
+
+1. example of text, which demonstrates and allows to reproduce spelling error;
+2. explanation, why produced spelling is wrong and how it should be corrected.
+
 ## Steps for your contribution
 <a class="anchor" id="step1">1. Get familiar with [additive speech synthesis](https://en.wikipedia.org/wiki/Speech_synthesis#Formant_synthesis).
 
@@ -29,13 +33,13 @@ to view and discuss other related topics.
 
 <a class="anchor" id="step6">6. Make your improvements (i.e. additions or modifications) and check your project with `make check` command. Fix issues if necessary.
 
-<a class="anchor" id="step7">7. If you contribute to an existing language, find language maintainer in language configuration file located in `espeak-ng-data/lang` folder[<sup>1</sup>](#1) and ask him to review your changes. If you can't find language maintainer, you can review list of all contributors[<sup>2</sup>](#2) and contact them. You can also volunteer to become language maintainer just by updating language configuration file.
+<a class="anchor" id="step7">7. If you contribute to an existing language, find language maintainer in language configuration file located in `espeak-ng-data/lang` folder[<sup>1</sup>](#1) and ask him to review your changes. If you can't find language maintainer, you can review list of all contributors[<sup>2</sup>](#2) and contact them. You can also volunteer to become language maintainer just by updating [language configuration file](voices.md) and submitting your changes as it is described in [step 9](#9).
 
-<a class="anchor" id="step8">8. [Push your changes to GitHub](https://help.github.com/en/articles/pushing-commits-to-a-remote-repository) and create [pull request](https://help.github.com/en/articles/creating-a-pull-request). You can also send changed files by email to [eSpeakNG mailing list](https://groups.io/g/espeak-ng) (but then inlusion of them may take more time).
+<a class="anchor" id="step8">8. If you contribute to the core of espeak-ng engine (i.e. source files of software), you may just issue pull requests as described in [step 9](#9). Note that `make check` must pass and there should not be merging conflicts (and for new/extended functionality new tests should be created). If you are ready to take responsibility, ask [current maintainers](https://github.com/espeak-ng/espeak-ng/people) to get promoted as a maintainer of the project.
 
-<a class="anchor" id="step9">9. Wait for feedback of current espeak-ng maintainers[<sup>3</sup>](#3).
+<a class="anchor" id="step9">9. [Push your changes to GitHub](https://help.github.com/en/articles/pushing-commits-to-a-remote-repository) and create [pull request](https://help.github.com/en/articles/creating-a-pull-request). You can also send changed files by email to [eSpeakNG mailing list](https://groups.io/g/espeak-ng), but then inlusion of them may take more time.
 
-<a class="anchor" id="step10">10. If you feel ready to take responsibility, ask existing maintainers to become promoted as a maintainer of the project.
+<a class="anchor" id="step10">10. Wait for feedback of current espeak-ng maintainers[<sup>3</sup>](#3).
 
 ----