Fall Back to Basic/Built-In Autocomplete When No Language Server?

[treatmesubj]

Hi, I use lsp-zero and nvim-cmp as recommended in the docs. I enjoy Ctrl+N autocomplete when I am working on a filetype for which I have a language server installed. However, when I work on a file like markdown, for which I do not have a language server installed, I wish that I had the old-school basic/built-in autocomplete functionality of Ctrl+N, however it doesn't seem to work or do anything anymore.

Is it possible to configure this?

Here is the top of my ~/.vimrc...

" ~/.vimrc
call plug#begin('~/.vim/plugged')
Plug 'patstockwell/vim-monokai-tasty'
Plug 'vim-python/python-syntax'
Plug 'jlanzarotta/bufexplorer'
Plug 'mogelbrod/vim-jsonpath'
Plug 'itchyny/lightline.vim'
Plug 'treatmesubj/rock-lightline'
if has('nvim')
  Plug 'wookayin/semshi'
  " LSP Support
  Plug 'neovim/nvim-lspconfig'
  " Autocompletion
  Plug 'hrsh7th/nvim-cmp'
  Plug 'hrsh7th/cmp-nvim-lsp'
  Plug 'L3MON4D3/LuaSnip'
  " LSP-Zero
  Plug 'VonHeikemen/lsp-zero.nvim', {'branch': 'v3.x'}
  Plug 'nvim-treesitter/nvim-treesitter', {'do': ':TSUpdate'}
  " :TSInstall yaml
  Plug 'cuducos/yaml.nvim'
endif
call plug#end()

and here's top of my ~/.config/nvim/init.lua...

-- ~/.config/nvim/init.lua
vim.api.nvim_command('set runtimepath^=~/.vim runtimepath+=~/.vim/after')
vim.api.nvim_command('let &packpath = &runtimepath')
vim.api.nvim_command('source ~/.vimrc')

local lsp_zero = require('lsp-zero')
lsp_zero.on_attach(function(client, bufnr)
  lsp_zero.default_keymaps({buffer = bufnr})

  --if client.server_capabilities.documentSymbolProvider then
  --  require('nvim-navic').attach(client, bufnr)
  --end
end)
-- show most severe errors on top
vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(
    vim.lsp.diagnostic.on_publish_diagnostics, {
        severity_sort = true
    }
)
-- https://github.com/neovim/nvim-lspconfig/blob/master/doc/server_configurations.md
-- https://github.com/python-lsp/python-lsp-server
require('lspconfig').pylsp.setup{
  cmd = {(os.getenv("HOME")..'/.venv_pynvim/bin/pylsp')};
  settings = {
    pylsp = {
      plugins = {
        jedi = {
          environment = (os.getenv("HOME")..'/.venv_pynvim/bin/python')
        }
      }
    }
  },
}

Response to my discussion in nvim-cmp suggests it may be possible with cmp-buffer and cmp-path.

I have noticed removing this below section does bring old-school basic/built-in autocomplete functionality of Ctrl+N back.

local lsp_zero = require('lsp-zero')
lsp_zero.on_attach(function(client, bufnr)
  lsp_zero.default_keymaps({buffer = bufnr})
end)

[treatmesubj]

Whoops, actually the exact cmp source I needed was described right in the docs!