deviseで登録情報がsaveできない

前提・実現したいこと

現在、rubyを使って、プラットフォームアプリを作成しています。
deviseを導入して、複数モデルを作成し、ログインを実行したところ
保存がされていませんでした。通常通りログインができるようにしたいです。
初学者ゆえ、もろもろ抜けているところなどありましたら、ご指摘いただければと思います。

発生している問題・エラーメッセージ

ターミナル

Started POST "/speakers" for ::1 at 2020-10-01 14:33:00 +0900
Processing by Speakers::RegistrationsController#create as HTML
  Parameters: {"authenticity_token"=>"cMpj1qCQPUrcY8s44bXNgiKuqAIsaUdlQThsr0H4h63nFNKe+8+r6dMc5ewH/vLk5iIJxh1vj86UWztsmmKRVg==", "speaker"=>{"nickname"=>"wa", "email"=>"wa@wa", "password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]", "first_name"=>"あ", "last_name"=>"あ", "first_name_kana"=>"ア", "last_name_kana"=>"ア", "birth_date(1i)"=>"1931", "birth_date(2i)"=>"6", "birth_date(3i)"=>"5"}, "commit"=>"会員登録"}

From: /Users/yuuri/projects/wacca/app/controllers/speakers/registrations_controller.rb:15 Speakers::RegistrationsController#create:

    13: def create
    14:   @speaker = Speaker.new(speaker_signup_params)
 => 15:   binding.pry
    16:   if @speaker.save
    17:     redirect_to root_path
    18:   else
    19:     render :new
    20:   end
    21: end

[1] pry(#<Speakers::RegistrationsController>)> @speaker
=> #<Speaker id: nil, first_name: nil, last_name: nil, first_name_kana: nil, last_name_kana: nil, nickname: "", email: "", birth_date: nil, created_at: nil, updated_at: nil>
[2] pry(#<Speakers::RegistrationsController>)>

コントローラー

# frozen_string_literal: true

class Speakers::RegistrationsController < Devise::RegistrationsController
  before_action :speaker_signup_params, only: [:create]
  # before_action :configure_account_update_params, only: [:update]

  # GET /resource/sign_up
    def new
      @speaker = Speaker.new
    end

  #  POST /resource
    def create
      @speaker = Speaker.new(speaker_signup_params)
      if @speaker.save
        redirect_to root_path
      else
        render :new
      end
    end

  # GET /resource/edit
  # def edit
  #   super
  # end

  # PUT /resource
  # def update
  #   super
  # end

  # DELETE /resource
  # def destroy
  #   super
  # end

  # GET /resource/cancel
  # Forces the session data which is usually expired after sign
  # in to be expired now. This is useful if the user wants to
  # cancel oauth signing in/up in the middle of the process,
  # removing all OAuth session data.
  # def cancel
  #   super
  # end

   protected

  # If you have extra params to permit, append them to the sanitizer.
   def speaker_signup_params
     devise_parameter_sanitizer.permit(:sign_up, keys: [:first_name,:last_name,:first_name_kana,:last_name_kana,:email,:nickname,:birth_date])
   end

  # If you have extra params to permit, append them to the sanitizer.
  # def configure_account_update_params
  #   devise_parameter_sanitizer.permit(:account_update, keys: [:attribute])
  # end

  # The path used after sign up.
  # def after_sign_up_path_for(resource)
  #   super(resource)
  # end

  # The path used after sign up for inactive accounts.
  # def after_inactive_sign_up_path_for(resource)
  #   super(resource)
  # end
end