yaml_encoding_fun.rb

# encoding: utf-8

require "yaml"
require "yaml/encoding" 

input_for_yaml = {
                    :phonetic_notation => "[ə’kɒmplɪʃ]",
                    :words => ["schaffen", "vollbringen", "vollenden", "leisten", "durchführen"]
                  }

File.open "file.yml", 'w:utf-8' do |f|
  f << YAML.unescape(YAML.dump(input_for_yaml)).force_encoding("UTF-8")
end

p YAML.load_file("file.yml") # {:phonetic_notation=>"[ə’kɒmplɪʃ]", :words=>["schaffen", "vollbringen", "vollenden", "leisten", "durchführen"]}

# file.yml content
# --- 
# :phonetic_notation: "[ə’kɒmplɪʃ]"
# :words: 
# - schaffen
# - vollbringen
# - vollenden
# - leisten
# - "durchführen"