Add German conjugation instruction

README.md

@@ -5,23 +5,57 @@ Wilhelm Vocabulary
 ![GitHub workflow status badge][GitHub workflow status]
 [![Apache License Badge]](https://www.apache.org/licenses/LICENSE-2.0)
 
-- [Wilhelm Vocabulary](#wilhelm-vocabulary)
-  - [YAML Schema](#yaml-schema)
-    - [German](#german)
-    - [Korean](#korean)
-    - [Classical Hebrew (Coming Soon)](#classical-hebrew-coming-soon)
-    - [Ancient Greek](#ancient-greek)
-    - [Latin](#latin)
-  - [License](#license)
-
 The data that serves [wilhelmlang.com](https://wilhelmlang.com/). They are written in YAML format, because
 
 1. it is machine-readable so that it can be consumed quickly in data pipelines
 2. it is human-readable and, thus, easy to modify
 3. it supports multi-lines value which is very handy for data of natural languages
 
-YAML Schema
------------
+[German](./german.yaml)
+-----------------------
+
+### YAML Schema
+
+```yaml
+vocabulary:
+  - term: string
+    definition: list
+    plural: string
+    declension/conjugation: application-specific table
+```
+
+- The `conjugation` is the inflection paradigm for a German verb and `declension` the inflection for nouns and
+  adjectives. Only one of the two is present for a term.
+- The type of the word can be inferred using the following rule
+
+    - `term` with a _definite article_ of __der__/__die__/__das__ signifies a __noun__. For instance
+
+      ```yaml
+        - term: die Wissenschaft
+          definition: the Science
+      ```
+
+    - Those with `conjugation` field denotes a __verb__; its definition also begins with an _indefinite form_, i.e.
+      "to ..."
+    - The rests are explicitly stated in the `definition` field. For example,
+
+      ```yaml
+        - term: ob
+          definition:
+            - (conj.) if
+            - (conj.) whether
+      ```
+
+      means "ob" is a **conjunction** in this case and
+
+      ```yaml
+        - term: denn
+          definition:
+            - (adv.) then, thus
+            - (conj.) because
+      ```
+
+      tells that "denn" can be __adverb__ or __conjunction__
 
 > [!TIP]
 >
@@ -53,76 +87,83 @@ YAML Schema
 > __Visualzing synonyms this way presents a big advantage to human brain__ who is exceedingly good at memorizing
 > patterns
 
-### [German](./german.yaml)
+### German Noun Declension
+
+The declension table employees an [application-specific YAML](https://stackoverflow.com/q/30894438/14312712) that looks like the following:
 
 ```yaml
-vocabulary:
-  - term: string
-    definition: list
-    plural: string
-    declension/conjugation: application-specific table
+  - term: ein
+    definition: (article) a, an
+    declension:
+      - ["",         masculine, feminine, neuter, plural]
+      - [nominative, ein,       eine,     ein,    N/A   ]
+      - [genitive,   eines,     einer,    eines,  N/A   ]
+      - [dative,     einem,     einer,    einem,  N/A   ]
+      - [accusative, einen,     eine,     ein,    N/A   ]
 ```
 
-- The `conjugation` is the inflection paradigm for a German verb and `declension` the inflection for nouns and
-  adjectives. Only one of the two is present for a term.
-- The type of the word can be inferred using the following rule
+The declension table above is equivalent to
+
+|                | masculine | feminine | neuter | plural |
+|:--------------:|:---------:|:--------:|:------:|:------:|
+| __nominative__ |    ein    |   eine   |  ein   |  N/A   |
+|  __genitive__  |   eines   |  einer   | eines  |  N/A   |
+|   __dative__   |   einem   |  einer   | einem  |  N/A   |
+| __accusative__ |   einen   |   eine   |  ein   |  N/A   |
 
-  - `term` with a _definite article_ of __der__/__die__/__das__ signifies a __noun__. For instance
+> [!NOTE]  
+> - A list under `declension` is a table row
+> - All rows have the same number of columns
+> - Each element of the list corresponds to a table cell
 
-    ```yaml
-      - term: die Wissenschaft
-        definition: the Science
-    ```
+> [!TIP]
+> __The declension tables for all nouns are sourced from
+> [Wiktionary](https://en.wiktionary.org/wiki/ein#Declension_2)__
+
+### German Verb Conjugation
 
-  - Those with `conjugation` field denotes a __verb__; its definition also begins with an _indefinite form_, i.e.
-    "to ..."
-  - The rests are explicitly stated in the `definition` field. For example,
+There are __3__ persons, __2__ numbers, and __4__ moods (indicative, conditional, imperative and subjunctive) to
+consider in conjugation. There are __6__ tenses in German: the present and past are conjugated, and there are four
+compound tenses. There are two categories of verbs in German:
+[weak and strong](https://en.wikipedia.org/wiki/Germanic_strong_verb)[^1]. In addition,
+[strong verbs are grouped into 7 "classes"](https://en.wikipedia.org/wiki/Germanic_strong_verb#Strong_verb_classes)
 
-    ```yaml
-      - term: ob
-        definition:
-          - (conj.) if
-          - (conj.) whether
-    ```
+[^1]: https://en.wikipedia.org/wiki/German_verbs#Conjugation
 
-    means "ob" is a **conjunction** in this case and
+The conjugation table of German verb on Wiktionary is hard to interpret as a German language learner. It does, however,
+presents a very good Philology reference. For example, it tells us which of the 7 "classes" a strong verb belongs to.
+__We, therefore, leave the Wiktionary links to the conjugation table of that verb for data processing in the future__,
+for example,
 
-    ```yaml
-      - term: denn
-        definition:
-          - (adv.) then, thus
-          - (conj.) because
-    ```
+```yaml
+  - term: aufwachsen
+    definition: to grow up
+    conjugation: https://en.wiktionary.org/wiki/aufwachsen#Conjugation
+```
 
-    tells that "denn" can be __adverb__ or __conjunction__
+and advise user to employ a much more practical method to learn daily conjugation as follows. We take __aufwachsen__ as
+an example.
 
-- The declension/conjugation table employees an
-  [application-specific YAML](https://stackoverflow.com/q/30894438/14312712) that looks like the following:
+> [!IMPORTANT]  
+> I'm not advertising for any organizations. I'm simply sharing good resources.
 
-  ```yaml
-    - term: ein
-      definition: (article) a, an
-      declension:
-        - ["",         masculine, feminine, neuter, plural]
-        - [nominative, ein,       eine,     ein,    N/A   ]
-        - [genitive,   eines,     einer,    eines,  N/A   ]
-        - [dative,     einem,     einer,    einem,  N/A   ]
-        - [accusative, einen,     eine,     ein,    N/A   ]
-  ```
+[Netzverb Dictionary](https://www.verbformen.com/) is the best German dictionary _targeting the vocabulary inflection_.
+Search for "aufwachsen" and we will see much more intuitive conjugation tables listed. This pretty much serves our
+needs, but what makes Netzverb unpenetrable by other dictionaries is that _every_ verb comes with
 
-  The declension table is equivalent to
+1. [A printable version that looks much better than the browser's Control+P export](https://www.verbformen.com/conjugation/aufwachsen.pdf)
 
-  |                | masculine | feminine | neuter | plural |
-  |:--------------:|:---------:|:--------:|:------:|:------:|
-  | __nominative__ |    ein    |   eine   |  ein   |  N/A   |
-  |  __genitive__  |   eines   |  einer   | eines  |  N/A   |
-  |   __dative__   |   einem   |  einer   | einem  |  N/A   |
-  | __accusative__ |   einen   |   eine   |  ein   |  N/A   |
+   - A "Sentences with German verb aufwachsen" section with a
+     [link](https://www.verbformen.com/conjugation/examples/aufwachsen.htm) that offer a fruitful number of conjugated
+     examples that get us familiar with the inflections of the verb
 
-  __The declension/conjugation tables for all vocabularies are sourced from
-  [Wiktionary](https://en.wiktionary.org/wiki/ein#Declension_2)__
+2. [An on-the-fly generated flashcard sheet](https://www.verbformen.com/conjugation/worksheets-exercises/lernkarten/aufwachsen.pdf)
+   which allows us to make a better usage of our random free time
+3. [A YouTube video that offers audios of almost every conjugated form](https://www.youtube.com/watch?v=LCtUrSn030A),
+   which helps with conjugated pronunciations.
 
-### [Korean](./korean.yaml)
+[Korean](./korean.yaml)
+-----------------------
 
 中国人学习韩语有先天优势，加之韩语本身也是一门相当简单的语言，所以这里将语法和词汇合并在一起；
 每一项也只由 `term`（韩）和 `definition`（中）组成，
@@ -135,12 +176,14 @@ vocabulary:
 
 不用费太多功夫记牢简单的语法和词汇，剩下的就是拿韩语字幕剧不停练习听说读写既成。
 
-### Classical Hebrew (Coming Soon)
+Classical Hebrew (Coming Soon)
+------------------------------
 
 The vocabulary is presented to help read and understand [Biblical Hebrew](https://mechon-mamre.org/p/pt/pt00.htm#mp3). A
 [complementary audio](https://mechon-mamre.org/p/pt/ptmp3prq.htm) helps well with the pronunciation.
 
-### [Ancient Greek](./greek.yaml)
+[Ancient Greek](./greek.yaml)
+-----------------------------
 
 ```yaml
 vocabulary:
@@ -148,7 +191,8 @@ vocabulary:
     definition: list
 ```
 
-### [Latin](./latin.yaml)
+[Latin](./latin.yaml)
+---------------------
 
 ```yaml
 vocabulary:

german.yaml

@@ -538,7 +538,7 @@ vocabulary:
   - term: die Kirche
     definition: the church
   - term: der Supermarkt
-    definition: supermarket
+    definition: the supermarket
     declension:
       - ["",         singular, singular, singular,                    plural, plural      ]
       - ["",         indef.,   def.,     noun,                        def.,   noun        ]
@@ -915,6 +915,13 @@ vocabulary:
     definition: leave here
   - term: Schon gut.
     definition: It's okay
+  - term: aufwachsen
+    definition: to grow up
+    conjugation: https://en.wiktionary.org/wiki/aufwachsen#Conjugation
+
+
+
+
   - term: der Volksgenosse
     definition: countryman
     declension: https://www.verbformen.com/?w=Volksgenosse