CI3 (Twig) Query result array is empty

You don't need ->select("*"). From CodeIgniter docs:

$this->db->select()

...

If you are selecting all (*) from a table you do not need to use this function. When omitted, CodeIgniter assumes that you wish to select all fields and automatically adds ‘SELECT *’.

So you can do just this:

$query = $this->db->get("phrases")->result_array();

By the way, I think that e.g. $phrases would be a better variable name.

Another doc page describes the result_array() method:

This method returns the query result as a pure array, or an empty array when no result is produced. Typically you’ll use this in a foreach loop.

So, $query is an array, so you need to loop through it in Twig. The array is not empty, you even posted its contents to your question. I expanded the contents to multiple rows for readability:

[    0 => [        'id' => '31',        'keyword' => 'hello_world',        'value' => 'Hello World',        'language' => 'english'    ],    1 => [        'id' => '35',        'keyword' => 'beautiful_weather',        'value' => 'It\'s a beautiful weather today',        'language' => 'english'    ],    2 => [        'id' => '36',        'keyword' => 'goodbye',        'value' => 'Goodbye!',        'language' => 'english'    ],    3 => [        'id' => '37',        'keyword' => 'test',        'value' => 'Test123',        'language' => 'english'    ]]

So, you have four items and each of them has keys id, keyword, value and language. You can loop through the array in Twig e.g. like this:

{% for item in query %}    ID is {{ item.id }}    Keyword is {{ item.keyword }}    Value is {{ item.value }}    Language is {{ item.language }}{% endfor %}

Output:

ID is 31Keyword is hello_worldValue is Hello WorldLanguage is englishID is 35Keyword is beautiful_weatherValue is It's a beautiful weather todayLanguage is englishID is 36Keyword is goodbyeValue is Goodbye!Language is englishID is 37Keyword is testValue is Test123Language is english

Edit:

You can perform the foreach loop in PHP like this:

$phrase = [];foreach ($query as $result) {    $phrase[$result->keyword] = $result->value;}$this->twig->addGlobal("phrase", $phrase);

And then in Twig:

{{ phrase.hello_world }}{{ phrase.beautiful_weather }}{{ phrase.goodbye }}{{ phrase.test }}